In spite of the great amount of attention which has been bestowed upon this group by many workers, it must still be said that our knowledge of its systematic position is very meagre and uncertain, and that there are points in its anatomy which require elucidation. Through the kindness of Professor M‘Intosh I have been enabled to examine some specimens of P. australis, and also a Phoronis, which appears to be a new species. I reserve a detailed account of my results for later publication, and here only refer very briefly to leading points. I may mention that Professor M‘Intosh has also allowed me the inspection of his serial sections of P. buskii. M‘Intosh, and after a careful comparison I have not the slightest doubt that this is a distinct species from P. australis—it has been usual to regard the distinction between these two forms as not of specific value.

Divisions of the Body.—It is usual, in describing the structure of Phoronis, to refer to two different parts of the body which lie before and behind the septum respectively. I propose, for reasons shown later, to emphasise the division of the body into—(1) The epistome, lying dorsally to the mouth, and having very definite, though somewhat involved, relationship to the next part; (2) the tentacular region, which I prefer to call the collar, consisting of a ring round the mouth region, the oral part being produced into two arms or processes which bear tentacles and are coiled, and the aboral end being limited superficially by the nerve ring and fundamentally by the so-called septum; (3) the trunk, including all the region behind the septum.