An Ischnopsyllus Westw., 1833, lately sent by Miss Kuei-Chen Li, National Kweiyang Medical College, China, differs considerably from all the known Ischnopsyllus and suggests that the species are as numerous in China as in Europe. Inclusive of Miss Li's specimens four eight-combed species from China are represented in the British Museum, all that have so far been described from that country. We are much indebted to Miss Li for the new species and to Mr Yin-ch'i Hsü for paratypes of two bat-fleas described by him

1. The structure of the proboscides of the larva of Dibothriorhynchus grossum (Rud.) is described. Each proboscis is provided with four sets of extrinsic muscles, and there is an anterior dorso-ventral muscle mass connected to all four proboscides.

2. The musculature of the body and scolex is described.

3. The nervous system consists of a brain, two lateral nerve cords, two outer and inner anterior nerves on each side, twenty-five pairs of bothridial nerves to each bothridium, four longitudinal bothridial nerves connecting these latter before their entry into the bothridia, four proboscis nerves arising from the brain, and a series of lateral nerves supplying the lateral regions of the body.

4. The so-called ganglia contain no nerve cells, these are present only in the posterior median commissure which is therefore the nerve centre.

The trematode and cestode parasites of fishes inhabiting British coastal waters have been the subject of several studies in the past, but the parasites of deep-sea fishes have received comparatively little attention due probably to the difficulty of obtaining fresh material. In order that such material might be obtained, excursions were made by the junior author in a commercial trawler to some of the deep-sea fishing grounds lying to the west of Ireland, namely, the Irish Atlantic Slope and the Porcupine Bank. Two excursions were made, the first in August 1938 and the second in July 1939, each extending over a period of about 12 days. In addition, a study has been made of the parasites of some fishes from the Irish Sea from 1936 to 1939. The results of both surveys are incorporated in this paper, and the areas investigated are indicated in Table 1.

1. Choricotyle chrysophryi van Beneden & Hesse has been recorded for the first time since its original discovery in 1863, and from a new host Pagellus centrodontus (De la Roche).

2. The history of C. chrysophryi and of allied species has been reviewed, resulting in the substitution of the generic name Choricotyle van Beneden & Hesse, 1863 for Diclidophora Goto, 1894 and the family name Choricotylidae nov. for Diclidophoridae Fuhrmann, 1928.

3. The anatomy of Choricotyle chrysophryi has been investigated by means of serial sections, revealing specialized features in the presence of a terminal languette and of a ‘ring-organ’.

Samples of Peringia ulvae were collected and measured on eight occasions, over a period of two years from an isolated pool in the saltings of the River Tamar. Growth conditions in this pool are at a maximum. Spawning occurs in the autumn and the greatest number of small specimens are found in the sieve (1 mm. mesh) in February. Maximum growth takes place during April-July. After ten months of age,.uninfected snails which have reached a length of 5¾ mm. grow only 1–1¼ mm., and gradually die off from 17 months of age onwards. Infected snails display gigantism and variation and attain dimensions of 9–10 mm. They are probably no older than uninfected specimens measuring 6¾ mm. long.

The infection rate is high and shows certain seasonal fluctuations, no doubt linked with the migrations of the wading birds which are the principal final hosts of the trematodes.

1. The family Diclidophoridae Fuhrmann, 1928 has been revised, and the diagnosis of the replacing family Choricotylidae has been given.

2. Keys to the genera and species of the Choricotylidae have been constructed.

3. All species of the family have been reviewed and a diagnosis of each has been given.

4. Species previously referred to the genus Diclidophora have been transferred to the genus Choricotyle.

5. The following taxonomic changes have been proposed:

(a) Choricotyle merlangi (MacCallum, 1917) as a nom. nov. for the ‘Diclidophora merlangi Kuhn, 1829’ described by MacCallum (1917).

(b) Choricotyle charcoti (Dollfus, 1922 a, b) as a n.comb. to replace Cyclo-bothrium charcoti Dollfus, 1922.

(c) Diclidophora ‘species’ Fuhrmann, 1928 as a synonym of Choricotyle charcoti (Dollfus, 1922a, b).

Specimens of Plectanocotyle gurnardi were obtained by the writer from the gills of Trigla cuculus L. and T. gurnardus L. during trawling operations at the Irish Atlantic Slope fishing grounds in August 1938 and July 1939. One specimen of Plectanocotyle gurnardi was collected from a Trigla gurnardus and seven specimens of the same parasite from eight specimens of T. cuculus, the greatest degree of infestation encountered being 3 parasites per host fish. Plectanocotyle gurnardi has been recorded previously, under one or other of the synonyms listed above, from Trigla gurnardus by van Beneden & Hesse (1863), T. Scott (1901, 1905), A. Scott (1904), Lebour (1908), and Little (1929); from T. lucerna L. by A. Scott & Little; and from Trigla ‘sp.’ by Monticelli (1899). It will be noted that the present records of the parasite are from its usual host T. gurnardus and from a new host T. cuculus.

The following is an account of the anatomy of the scolex of Aporhynchus norvegicus (Olss.) involving details of the musculature and nervous and excretory systems. The anatomy of the strobila has been described by Nybelin (1918). The specimens, mostly young complete strobilae, were obtained from the intestine of Spinax spinax caught in the deep-sea fishing grounds to the west of Ireland. Until recently the species had only been recorded from the coast of Norway, but in 1936 Joyeux & Baer found it in French waters. It was first described as Tetrarhynchus norvegicus by Olsson (1867), the genus Aporhynchus being created by Nybelin (1918) for the single species.

The metacercaria shown in Fig. 1 was obtained in the laboratory from Gobies (Gobius ruthensparri Euphras.) experimentally infected with a Pleurolophocerca cercaria from Peringia ulvae. This cercaria is regarded as the most interesting of all the Heterophyid larvae infecting this snail. It has been referred to briefly in a previous publication (Rothschild, 1938). It differs from typical Opisthorchid cercariae in the following characteristics:

(1) The lateral fin-folds are continuous and extend the whole length of the tail. The dorso-ventral fin-fold is reduced.

(2) The oesophagus and intestinal caeca (in addition to the pharynx) can be clearly made out.

(3) The cuticle is more heavily spined.

(4) The ventral sucker is better developed.

(5) The penetration gland ducts (fourteen in number) are not arranged in such definite bundles.

(6) Three acicular boring spines are present in the oral sucker.

In other respects the cercaria possesses the usual characters of the group.

Numerous specimens of a trematode which has proved to be a new species were collected from the kidneys of 'Ular sawa’ (Python reticulatus) at Alor Star and at Kedah, Malaya, by Mr G. B. Purvis, F.R.C.V.S. One batch comprises about 350 specimens, another one more than 150, and the entire collection of five batches exceeds 600 specimens. For this new species the name Styphlodora elegans is proposed. Mr Purvis also collected a single specimen of what seems to be a second new species from the stomach of the python at Alor Star, and for this the name Styphlodora compactum is proposed. Type specimens of the two new species are lodged in the British Museum (Natural History), London.