STRUCTUR1-: AND ni'A'KT.OPMENT OF COKLOl'LANA. 37 



egg-cells of such stage, but my observation is not sure enough to 

 determine this. 



The above description on the ovary is based upon observations in 

 C. bocki. In the remaining two species, I could not find any mature 

 ^S&' probably because of the season when the material of those species 

 was secured. But, as far as could be ascertained from the available 

 material, the two species showed no distinguishing feature with respect 

 to the ovary; the largest nucleus of the ovarian eggs observed in those 

 species was \2 fi in diameter. 



There remains to be described certain peculiar structures, which 

 are to be looked upon as accessory parts of the ovary. These are deep 

 invaginations from the dorsal surface of the body, which are arranged 

 serially along all the subpharyngeal and subtentacular canals (PI. 5, figs. 

 I, 6, 7, 9-1 1 ; r. s). Each of them is tubular in the external part and is 

 expanded terminally into a globular ampulla-like or somewhat irregular- 

 shaped swelling situated quite close to and often in direct contact with 

 the ovarial membrane. The tubular part is sometimes approximately 

 straight, but at other times somewhat curved. Further, it may be nearly 

 perpendicular to the dorsal epidermis, but more frequently more or less 

 oblique to it. This part is made up of ciliated cells of a pyramidal form 

 with a large vesicular nucleus in the basal part of the cell (fig. 10; r. s. 

 t). The number of the cells appearing in a cross-section of the tube is 

 from six to ten. The internal lumen is rather spacious and roundish. 

 The terminal vesicle is clothed with flat cells containing each a vesicular 

 nucleus. The cytoplasm of the cells is sometimes tolerably compact 

 and shows diffuse ciliation, but at other times it is vacuolated or 

 attenuated and deprived of ciliation altogether. The former condition 

 is common when the ovary which the structure accompanies is still 

 immature and shows small egg-cells only, while the latter may be met 

 with when the ovary contains some large egg-cells. 



Sometimes, especially in the last-mentioned case, the invagination, 

 especially the terminal expansion, contains quite a large quantity of 

 spermatozoa (PI. 5, figs, i, 6, 7; spz). This observation makes it quite 

 possible that the structure serves as a seminal receptacle. I shall call 

 accordingly the structure by that name henceforth. 



The number of seminal receptacles found along each of the 

 subpharyngeal and subtentacular canals fluctuates within a wide limit 

 with the size of the animal. In the majority of cases, however, it may 

 be given as seven to thirteen to each subtentacular canal and four to 



