34 Mr. A. Hancock on the Anatomy of Antiopa Spinolse. 



sixteenth pair are larger than those of the other two, and pass 

 down the under surface of the CESophagus, parallel to each other, 

 on their way to the stomach. 



The gastro-oesophageal ganglions are undescribed by M. Blan- 

 chard, who states that they are not isolated in Janus from the 

 buccal ganglions. In my specimens, however, they were as 

 distinct as in any of the Nudibranchs, and further removed from 

 the buccal ganglions than usual. The gastro-cesophageal are 

 named by this naturalist the " ganglions aortiques," — evidently a 

 false appellation, as all their nerves are distributed to the ali- 

 mentary organs. 



The Reproductive Organs resemble those of Eolis and Doris, and 

 are of vast volume and complication ; they (PI. II. fig. 1 n, o, p) 

 lie on the right side of the visceral cavity immediately behind 

 the buccal mass. The sheath of the intromittent organ, female 

 channel, and vagina in communication with the spermatheca open 

 into one common vestibule, the lips of which, when the organs 

 are fully retracted, form a nipple-like swelling on the right side, 

 less than half-way down the body. The intromittent organ 

 (PI. III. fig. 6 a) lies in front of the other parts, and in its re- 

 tracted state appears to be of considerable dimensions, of a clavate 

 form, with the smaller extremity leading to the external opening. 

 The testis {b) is a rather short, stout tube forming two or three 

 convolutions, with one end united to the thick or inner termina- 

 tion of the penis, and the other, which tapers a little, to the 

 oviduct. 



The ovary is very ample, filling the greater portion of the 

 visceral cavity from the stomach backwards. It is composed of 

 two masses, one (PI. II. fig. ip) lying in front and a little to 

 the left of the other {p'). They are both made up of large 

 irregular lobules composed almost entirely of eggs. The oviduct 

 (PI. III. fig. 6 c) leaves the ovary as a very delicate, slender 

 tube, and is soon abruptly dilated (fig. 6 rf & fig. 7 c) into at least 

 five or six times its original diameter ; and is so continued on, in 

 a tortuous course, to the front of the mucus-gland ; then, bending 

 back upon itself, it again becomes excessively contracted, and 

 shortly afterwards receives the duct-like extremity of the testis 

 at a point (fig. 6 e & fig. 7 d) where the oviduct is once more 

 suddenly bent upon itself. After this it (fig. 6 / & fig. 7 e) is 

 slightly enlarged just befoi-e it unites with a very short duct 

 (fig. 7 h) from the spermatheca ; then, passing forward, it divides 

 into two portions or branches, one {j) of which sinks into the 

 mucus-gland near to the place of its union with the female 

 channel (fig. 6 i & fig. 7 f) leading to the external outlet close 

 behind the penis. It is by this branch that the mature ova pass 

 on being evacuated. The other branch (fig. 6 A; & fig. 7 i), which 



