A. M. Taylor 273 



but which have become enlarged so as to be more important than 

 their principals ? 



The female organ which is rather more difficult to observe is also 

 single. It lies moi;e dorsal to the alimentary canal anteriorly, but its 

 hinder part and the duct to the exterior lie to the right of the intestine. 

 The actual opening of the oviduct is, I think, median upon the ventral 

 surface. Its edge is uneven, almost serrated (PL III, fig. 5). It difiers 

 from the male organ in two well-marked respects. 



(a) Its opening to the exterior is some way anterior to the opening 

 of the alimentary canal, although still in the hinder part of the animal. 



(6) A blind pocket projects backwards behind the opening of the 

 duct which may be called a receptaculum ovarum as it seems to contain 

 ripe ova. Probably fertilisation takes place here and possibly some 

 part of development may be undergone here, in which case it would 

 be termed more correctly a uterus, but I have not so far seen any 

 advanced embryos or even segmental ova in it. 



The extreme anterior end of the organ is very like the corresponding 

 part of the male gland. It contains follicle cells and oogonia. As 

 in the case of the male one can see as one looks along the gland that 

 in the lower parts the oogonia pass into large oocytes (PI. Ill, fig. 2). 

 There is then a region in which all trace of a large nucleus is absent 

 and the cells are much crowded. This is no doubt the region in which 

 the meiotic phase is taking place, and is followed by a string of rounded 

 cells which again shew a nucleus. This I take to be the oocyte II 

 stage. Close to the lower end of the oviduct, just before the opening, 

 a second region in which the nuclei are absent probably represents 

 the last maturation stage or heterotype division, beyond which a few 

 "ova" may be seen. These seem to pass over the opening of the 

 oviduct into the uterus. 



There is another possible interpretation. Are the cells in this 

 so-called receptaculum ovarum or uterus really spermatozoa ? In this 

 case perhaps the ova do not pass into this pocket at all, and the pocket 

 is therefore a receptaculum seminis. 



A further question then arises — is this pocket really a diverticulum 

 of the oviduct or is it a depression in a surface (as is often the case 

 in receptacula seminii, e.g., oligochaeta) ? If so, is it homologous with 

 the depression in which the spicules of the male are situated? 



Nervous system. Very little has been made out about this. I can 

 find in some cases a band of tissue running across the oesophagus 

 which may very likely be a nerve collar. 



