318 MR. A. HA]!fCOCK ON THE ANATOMY 



advance of the anal orifice. The testis is composed of numerous 

 elongated, simple or lobed vesicles, which are placed with one 

 end in contact with the sides of the ovaries, and are arranged in 

 parallel order at right angles to them, fringing both sides of these 

 organs from end to end. From the proximate extremities of the 

 vesicles extremely delicate ducts pass across the surface of the 

 ovary, to which they are attached, and go to join the vas deferens 

 that extends along the middle line from end to end of each 

 ovigerous organ, and, advancing along the oviduct, terminates at 

 tlie extremity of that tube. 



I have not met with this peculiar arrangement of the genitalia 

 in any other species, though, after all, it is but, as it were, an 

 amplification of that which we have seen to exist in the compound 

 genital masses in Stycla tioberosa and its immediate allies. If 

 one of these masses were greatly elongated, so as to become tubu- 

 lar, and if the male vesicles were increased in number, their lower 

 extremities pulled from beneath the ovigerous sac, and stretched 

 out on the mantle, we should have something very similar to that 

 which subsists in Pelonaia. 



Another modification of these organs occurs in Stycla varia- 

 bilis, an uudescribed species related to Cynthia Canopus, Savigny. 

 In this the ovaries assume the form of distinct, wide, slightly 

 undulated tubes, of which there are two on the right and two on 

 the left side of the mantle, each haviug its own short nipple-like 

 oviduct, which opens into the cloaca, there being two on each 

 side of the anus. The testis is composed of numerous irregularly 

 lobulated vesicles scattered over the lower portion of the mantle, 

 in the vicinity of the posterior extremities of the ovaries, but with 

 which they have no connexion, each separate vesicle having its 

 own short nipple-like duct or vas deferens. 



The reproductive organs do not exhibit any great diversity in 

 the genus Molgula, the ovary and its testis being always com- 

 bined, and forming one or two elongated masses, in which, how- 

 ever, the two component elements can always be detected by the 

 aid of their colour and structure. The testis is composed of a 

 vast number of branched vesicles or csecal tubules, crowded to- 

 gether and sometimes assuming a dendritic appearance, while the 

 ovary seems to be a lobrdated sac, usually well filled with eggs. 



In M. conchilega there are two such masses, placed transversely, 

 which are generally irregular in form, but sometimes are broadly 

 fusiform, and a little arched. That on the right side of tlie 

 mantle lies uj)on the upper border of the intestine ; the other 



