96 Messrs. Hancock and Enibleton on the Anatomy of Eolis. 



bear a good deal of resemblance to those of the other Nudi- 

 branchiata as described by Cuvier ; but in assigning the peculiar 

 functions of the various parts, we differ from that distinguished 

 physiologist. It is however only after often-repeated careful dis- 

 section, observation and deliberate consideration that we venture 

 to dissent from such high authority, and we feel it incumbent 

 upon us to state generally in what points we differ, and the reasons 

 of our dissent. 



That part in Doris called by Cuvier testis answers to what we 

 call the mucus-gland : that it is not testis we are assured, by its 

 having no direct connexion with the male parts, but opens very 

 evidently into the female channel, of which it is an appendage ; 

 we have several times examined its secretion, and found it to cor- 

 respond exactly with the mucus-like matter that envelopes the 

 ova. Again, the convoluted tube, called by Cuvier penis, we be- 

 lieve to be the testis, and for the following reasons : — 1st. It is 

 not uncommon to find the true penis, exserted in specimens pre- 

 served in spirits : on examination of the parts of E. papillosa in 

 such case, the penis of Cuvier is still found in the interior of the 

 body as a closely convoluted tube, the coils of which are nearly 

 all attached to each other by fine filaments, as noticed in our de- 

 scription, and are therefore not susceptible of being unrolled and 

 made to act as an intromittent organ. A small portion however 

 is freer than the rest, and is often found at the base of the penis, 

 being prolonged also to its extremity as the excretoi-y duct of the 

 testis. 2ndly. Its internal structure and its contents are clearly 

 those of a glandular organ, and spermatozoa have been found in 

 it in E. coronata ; and lastly, its connexions as already pointed 

 out, namely with the penis at one end and with the oviduct at 

 the other, seem to indicate pretty accurately its character. 



The sac we have called spermatheca we have ventured so to 

 name, because we find it possesses a channel of communication 

 with the exterior and a direct connexion with the oviduct, besides 

 containing, as we have witnessed in E. papillosa and E. coronata, 

 abundant masses of densely packed spermatozoa. This organ is 

 doubtless the " vessie " of Cuvier. 



In passing from the Baron's description of the genitalia of 

 Doris, while we are glad to acknowledge that his plates and de- 

 scriptions have been of great service to us in confirming in many 

 points the result of our own dissections, we cannot help being sur- 

 prised that two other anatomists, who have so recently been en- 

 gaged upon the corresponding organs of some of the Eolidida, 

 have not availed themselves of the store of valuable information 

 accumulated by their illustrious precm'sor in the same path of in- 

 vestigation in his ' Memoires pour servir ' &c. — we allude to 

 MM. de Quatrefages and de Nordmann. If we turn to the former 



