128 Transactions. — Zoology. 



present the appearance of being little more than glandular 

 dilatations of the oesophagus itself ; in transverse sections, 

 however, the epithelium of the oesophagus can be here and 

 there detected, and it is totally different from the epithelium of 

 the glands ; the cells are much more elongated, and are more 

 deeply stained than the cells of the glands by the reagent used 

 (alum carmine) ; both the glandular cells and the epithelial 

 lining of the oesophagus are furnished with long cilia — a charac- 

 ter which distinguishes the calciferous glands of this species 

 from those of A. dissimilis, and from certain glands of other 

 earthworms (e.g., Urochcsta) which have been regarded as the 

 homologues of the calciferous glands. 



" Vascular System. — The dorsal vessel is like that of A. 

 multiporus ; it is completely double from end to end of the 

 body ; for the most part the two vessels are placed side by 

 side, but they do not fuse at the points where they traverse 

 the mesenteries ; on the gizzard the two dorsal vessels come 

 to be somewhat widely separated. The transverse vessels 

 uniting the dorsal with the ventral vessel form large con- 

 spicuously-dilated ' hearts ' in segments x.-xiii. (inclusive). 

 In all the points A. antarcticus agrees closely with both A. 

 multiporus and A. anncctens. 



"Septa. — The characters of the intersegmental septa 

 appear to offer useful specific characters in this genus ; in 

 some species a certain number of the anterior septa are 

 greatly thickened ; the number of septa which are thus en- 

 larged, and the degree in which their thickness is increased, 

 differ, for instance, in the present species and in A. multiporus. 

 In A. antarcticus the septa separating segments vii.-viii., 

 viii.-ix., ix.-x., x.-xi., xi.-xii., are specially thickened, par- 

 ticularly the last four. In A. multiporus the same septa, with 

 the addition of one in front and one behind, are thickened, 

 but not so much as in A. antarcticus. 



" Genital Organs. — The testes are two pairs of minute 

 bodies in segments x. and xi. ; each is attached to the anterior 

 septum of its segment close to the junction of the septum 

 with the body-wall ; it is placed exactly opposite to the funnel 

 of the vas deferens. The ovaries occupy a corresponding posi- 

 tion in segment xiii., the funnel of the oviduct having a 

 relation to them similar to that of the funnel of the vas 

 deferens to the testis. The two pairs of atria are situated in 

 the seventeenth and nineteenth segments respectively ; each 

 is a much-coiled glandular tube communicating with the ex- 

 terior by means of a narrower tube with thick muscular walls. 

 The structure of these organs presents, in fact, no differences 

 from other species. Venial seta are present on both the 

 seventeenth and nineteenth segments, as in most other species 

 of Acanthodrilus, but not in A. multiporus ; the mature penial 



