126 Transactions. — Zoology. 



so common among earthworms, have the most varied relations 

 to the septa of the segments containing them, though the 

 situation of the external aperture does not vary at all. Each 

 spermatheca consists of a large pouch with relatively thin 

 walls ; this communicates with the exterior by a short thick- 

 walled muscular duct ; this duct gives rise to a diverticulum, 

 which terminates in an enlarged caecal extremity, the surface 

 of which is furrowed. The difference between the spermathecae 

 of this species and those of A. nova-zealandice is that in the 

 latter the diverticula are sessile. 



"In A. roses the structure of the spermathecaB is quite the 

 same as in A. dissimilis : in both these worms the epithelium 

 of the diverticulum does not appear to be — originally — so dif- 

 ferent from that of the pouch, though it comes ultimately to 

 present a strikingly different appearance. The pouch itself 

 is lined with tall columnar cells ; in the interior of these 

 are formed spherical masses of secreted granules which 

 seem to closely resemble similar products described by 

 Goehlich in the spermathecae of Lumbricus. The epithe- 

 lium lining the pouch is slightly folded. The diverticulum 

 of A. toscb is, as I have already stated, composed of a rela- 

 tively long tube with muscular walls, which terminate in a 

 swollen, somewhat lobate, caecal extremity ; this latter has a 

 structure quite like that of the diverticulum of A. dissimilis and 

 of Neodrilus. The epithelium is much folded, so as to divide 

 the cavity of the diverticulum ; in places the columnar cha- 

 racter of the cells can be recognised, but for the most part they 

 are not clearly recognisable, for the reason that they have 

 become largely converted into balls of a viscous-looking sub- 

 stance which does not stain. So far as I have been able to 

 follow the formation of the colloid-looking masses, I am in- 

 clined to think that they are the product of a fusion between 

 smaller droplets which appear in the interior of the cells. 

 The secretion, when formed, does not seem to be evacuated 

 into the interior of the numerous cascal pouches which consti- 

 tute the extremity of the diverticulum, as it is in the sperma- 

 theca itself, but to remain where it was formed. In nearly 

 all the viscous drops were imbedded bundles of spermatozoa, 

 which were always very distinct in my preparations, owing to 

 the fact that they were deeply stained by the colouring re- 

 agents used (alum carmine and borax carmine). A superficial 

 examination of such a section almost conveyed the idea that 

 the spermatozoa were developed in the diverticulum, so close 

 is their relation to the epithelium. There can be little doubt, 

 however, that the function of these masses formed by the 

 breaking-down of the epithelium is to retain the spermatozoa 

 within the pouch until ready for transference to another indi- 

 vidual. The spermatopores of Acanthodrilus are not known, 



