Some time ago, in a short article on maturation in the liver fluke Fasciola hepatica (L.), Sanderson (1953) suggested that development might be gynogenetic on the grounds that she was unable to find any second maturation division nor any polar bodies. Nevertheless, the presence of two large “pronuclei” seemed to point to normal zygogenesis. Unable to come to any definite conclusion the author decided to investigate maturation in another digenetic trematode, Haplometra cylindracea (Zeder 1800) when ample supplies came to hand from class dissections of frogs.

Previous work has shown a sex difference dependant upon œstrogen-androgen balance, in the rate of clearance by the fowl liver of intravenously administered sodium bromosulphthalein. Further observations reported here indicate an apparent rapid fluctuation of the Œ-A balance which takes place in immature chickens, both sexes snowing what is interpreted as hyperœstrogenization about the age of twelve weeks. Attention is drawn to other evidence that profound metabolic and hormonal changes occur at this stage. The effect of exogenous sex-hormones on the clearance rate of BSP has been further studied, particularly the influence of extra androgen on adult males with aberrant clearances unassociated with liver lesions. More evidence for the relation between the rate of BSP clearance and the Œ-A balance is provided by the study of the effect of cessation of ovulation on the clearance, and the effect of the development of virilizing tumours at the site of the rudimentary right ovary after left ovariectomy. Other changes which confirm hyperœstrogenization as assessed by the BSP clearance test are (a) decrease of the packed cell volume, (b) the development of a precipitable phospholipid in the plasma, (c) renal vascular changes, (d) adrenal cortical hyperplasia, (e) a frequent association with oviduct ligament “fibroids” and persistent cystic right oviducts.

A standard nigrosin-eosin staining method in current use has been said to differentiate between live (unstained) and dead (stained) spermatozoa. In the present work, the method is applied to rabbit semen. The general results are comparable with those already obtained in the larger domestic animals. The effects of several technical and biological factors on staining capacity are evaluated, and the validity of the method is examined experimentally. Some statistical aspects are presented. The percentage of stained spermatozoa varies widely between rabbit males. To a large extent, any particular male preserves a characteristic percentage from one ejaculate to another. The percentage of stained spermatozoa is inversely related to the fertility of males as measured by the birth rate after natural mating.

Concurrently, an investigation was made of the incidence of a class of morphologically abnormal spermatozoa seen in the preparations. The classifications of spermatozoa by morphology and by staining capacity are highly correlated. For assessing semen quality, the morphological classification is considered to be as useful as the classification by staining capacity, and perhaps more useful.

Nigrosin-eosin staining of rabbit spermatozoa is discussed; firstly, in comparison with other animals and in relation to sources of variation; secondly, as a means of differentiating between live and dead spermatozoa; thirdly, as a means of assessing the fertility of semen; and fourthly, in relation to the alternative classification of spermatozoa by abnormal morphology.

A taxonomic review is provided of imagines of the forty-one known British species of Culicoides Latreille (Diptera, Ceratopogonidæ).

Four species new to science, C. cameroni, C. reconditus, C. segnis and C. machardyi are described from the British Isles.

The female of C. poperinghensis Goetghebuer is described for the first time. C. poperinghensis Goetghebuer and C. subfasciipennis Kieffer are recorded as new to the British Isles. C. lupicaris Downes and Kettle is defined anew. Distinguishing taxonomic characters are given for the females of C. achrayi Kettle and Lawson and C. pallidicornis Kieffer.

A number of female structural characters of taxonomic importance are discussed and described for all the British species: the antennal sensilla are found to be important as a group character and antennal ratio as a specific or subspecific character.

Descriptive notes with relevant taxonomic discussion are given for each species. The paper includes a key to species based on superficial characters and separate keys for each sex based on structural characters.

Assemblages of small spores are described from the Pumpherston Shell Bed, the Pumpherston Oil Shales, the Burdiehouse Limestone and a thin coal found within the latter rock in one locality, all from the Lower Oil-shale Group (Viséan) of the Lower Carboniferous of Scotland.

The assemblages from the Oil-shales and the Limestone, rocks generally regarded as being of non-marine origin, are found to be very much alike; and although they show some differences from that of the Pumpherston Shell Bed (a marine shale), all three assemblages have a general similarity of composition. A suggested relation is put forward between this uniformity and the conditions prevailing in the area of the Midland Valley of Scotland during deposition of the beds. Correlation with other areas is discussed. Five new species and ten new types are described.

In Meganyctiphanes the blood is pumped from the heart to the various regions of the body by way of a well-developed arterial system. It passes out of the open ends of the final sub-branches of the arteries into the various sinuses, finally collecting in the posterior ventral region of the thorax. From there, by the action of the pericardium and the muscles associated with the afferent branchial channels, it enters the afferent branchial channels whence it circulates through the branchial veins in the branchiæ, to the efferent branchial channels. The beating of the heart draws the blood into the pericardium whence it reaches the heart cavity by way of two pairs of ostia.

Evidence is presented that, in fowls, as in a number of mammals, intravenously administered sodium bromosulphthalein is excreted by the liver into the bile in several forms. These metabolites are not glucuronides, esters or sulphates, and in the fowl do not have the chromatographic mobilities or other characteristics of any of the amino acids described as conjugating with BSP in mammals. In all, three forms of BSP are detectable in fowl bile after administration of the dye, one, with the highest Rf. is unchanged BSP, the others are associated with ninhydrin positive material, and have lower Rf. values. Conjugation has been studied in young chickens and in adults, and the effects of sex hormones, cortisone and liver damage have been assessed. It is shown that a proportion of the injected BSP may be retained for some time in the liver as a colourless form, so that only prolonged alkaline hydrolysis of liver extract and homogenate results in its liberation as a detectable coloured form. The significance of this, and the effect of sex hormones in influencing the amount of conjugation and thus possibly affecting the rate of liver clearance of BSP is discussed, and evidence is presented that there exists an apparent inverse relationship between the amount of œstrogen as assessed by BSP liver-clearance test and the relative proportions of the two BSP conjugates in the bile. Also direct relationship may exist between the amount of œstrogen and the proportion of colourless BSP found in the liver.

A gravity survey has been made of a glacier-dammed lake in Dronning Louise Land, North-East Greenland. Corrections for the effect of the local topography and the regional Bouguer anomaly are made to the values of the acceleration due to gravity measured at about 230 points on the lake and its shores. From the differences between the corrected values at the lake stations and those of the shores, depths of water under the lake stations are calculated, and a contour map of the lake bottom is drawn. A submerged shelf, 75 metres below the present lake level, persists around the western part of the lake. This may be the shore-line of a pre-glacial lake.

The humoral mechanism controlling metamorphosis in larvæ of Calliphora vomitoria L. and Lucilia cæsar L. and controlling diapause in the latter has been investigated by experiments involving extirpation and implantation of certain organs and section of nerves to the corpus cardiacum. It is confirmed that the large lateral cells of Weismann's ring, the thoracic gland cells, produce a hormone which promotes the several processes covered by the term “pupation”, including the development of anlagen before puparium formation, puparium formation, the third larval moult and the last larval moult. The stimulus to thoracic gland activity is provided by the brain and is transmitted via the nerves from that organ to the corpus cardiacum. This stimulus is apparently humoral and is liberated from the corpus cardiacum into the blood.

The thoracic glands of L. cæsar larvæ are inactive during diapause. Implants of active C. vomitoria glands into L. cæsar diapause larvæ terminate diapause in the latter. The immediate cause of the arrest in development is the failure of the brain to activate the thoracic glands.

The chromosome constitution of the bisexual beetle Ptinus clavipes Panzer (2n = 18) and of its gynogenetic form P. clavipes f. mobilis Moore (3n = 27) have been investigated. The triploid mobilis lives in close association with the bisexual species and mates freely with the males. Eggs from virgin females never pass beyond the metaphase stage and successful completion of maturation is dependent on the presence of sperm. An endomitotic split is apparent in prophase chromosomes and leads to the formation of twenty-seven pseudobivalents which undergo a pseudomeiotic division. Only one maturation division has been observed. Although the fate of the activating sperm has not been resolved it is thought that sperm nuclei give rise to isolated haploid nuclei in some eggs and interfere with normal cleavage in others. Since the triploid form may also mate with males of Ptinus pusillus Sturm and P. fur. L. with reduced numbers of progeny the affinities of the gynogenetic form is discussed. This is the only known case of gynogenesis in Coleoptera.

Triethylenemelamine induces chromosomal aberrations in Drosophila and in mammals. In the present paper the effects of intraperitoneal injections of the drug on the fertility of male mice are related to its mutagenic activity. Males were given prolonged or short treatment with the drug and were mated to females at frequent intervals.

Male fertility was greatly reduced after either treatment, a result similar to previous findings in the rat. Sterility for the first few weeks was due to dominant lethals causing embryonic mortality, and to oligospermia from 30 days after the injection. Embryonic mortality was reduced after lower doses, being maximal between 11 and 14 days after the injection, and little or no oligospermia resulted from this treatment.

The drug probably acted directly on spermatogenic cells; spermatids being most sensitive to the induction of lethals and spermatogonia to destruction; these estimates were based on the known rate of spermatogenesis in the mouse. The sensitivity of the stages of spermatogenesis and the translocation frequency induced by the drug have some similarities to the effects of X-rays on the testis.

From a faunistic survey in Scottish waters, concentrated mainly in the sea lochs of the north-west coast and in the deep water in the North Sea off the east coast, thirty-two species of polychætes are listed which have not previously been recorded from these areas. Seven of the species are new records for British coastal waters or for the North Sea.

Analyses of winter and summer vertical migrations of Meganyctiphanes norvegica are given and the differences in behaviour pointed out. A vertical layering of size classes, larger specimens occurring deeper than smaller ones, is shown to exist during the day and night.

Four potential methods of feeding were found. The inter-relationships between vertical migration, feeding method used, and type of food eaten are discussed.

The relationship of carapace length to total length was found to depend on the state of maturity of M. norvegica.

M. norvegica matures at the age of 1 year, transference of the spermatophores taking place in January-February, the eggs being laid in March-April. The larvae take 2–3 months to reach adolescence and little growth in size takes place in the winter when the gonads are maturing. An age of 3 years may be attained but most only survive 1½—2 years.

The distribution within the Clyde Sea throughout the year is described. Most of the population were found to move to the North-east Arran Area for egg-laying.

A 24-hr. and annual periodicity of luminescence is described and correlated with the period of swarming of this species prior to spermatophore transference.

The immature stages of C. circumscriptus Kieff. are found in the mud of most Scottish salt marshes. The life cycle has been studied by means of laboratory cultures and by observation and periodic sampling at a salt marsh near Dumbarton. Data are given concerning the life cycle in the laboratory and out of doors. In the field there are two generations a year.

In captivity the female lays a single large batch of eggs which adhere to the substrate by means of structures on the chorion. The eggs and the manner of oviposition and hatching are described. Descriptions of the larvae, supplementing those of previous authors are given. The first instar differs from older larvae in possessing a retractable prothoracic proleg, and is more sluggish in its movements, probably remaining near the oviposition site until the first ecdysis. Before pupation the larva comes to the surface. This is necessary for successful pupation, enabling the pupa to breathe and to form the buoyancy space. The pupa buries itself in the mud emerging only under flooded conditions to float on the surface or prior to ecdysis.

The distribution of thiol (sulphydryl) groups in the wool follicle has been studied with Bennett's reagent; the strongest reaction was found immediately proximal to the prekeratinization (keratogenous) region. Mice and lambs were injected with cystine labelled with sulphur-35 and radioactivity was detected in the follicles, autoradiographically within a few minutes. A peak of activity formed in the follicle during the first few hours after injection which suggested that there is a rapid turnover of cystine in the body. But a small amount of activity could still be detected in the follicle up to at least 3 weeks afterwards.

Sulphur seems to enter the follicle immediately above the bulb, and reaches the fibre first on the side at which it is keratinized last. This method indicated the relative proportion of sulphur in different regions of the follicle and suggested that the sulphur becomes concentrated on keratinization. No difference in sulphur content was found between primary and secondary follicles, the ortho- and paracortex, and apparently between cortex and medulla. When labelled sulphate was injected, activity appeared first in the outer sheath, and only later in the fibre.