412 Messrs. Alder and Hancock on a proposed New Order 



appearance of the spermatheca. Further than this, these organs 

 seem to have escaped observation. 



In Cenia and Acteonia we have not been able to investigate 

 the reproductive organs ; they both, however, have the intro- 

 mittent organ provided with a curved crystalline spur- like point. 



The generative system of Actceon {Elysia), as given by Pro- 

 fessor Allman, appears to have a considerable resemblance to that 

 of Limapontia. We think we can recognise the same parts, 

 though Professor Allman differs from us in assigning to them 

 their various functions. To arrive at a just conclusion on this 

 difficult subject, it is necessary, in the first place, to ascertain the 

 position of the external orifices, and their connexion with the 

 several parts of these complicated organs. Unfortunately in 

 Act(Bon these points could not be determined. In Limapontia, 

 on the contrary, we have had the good fortune to succeed in 

 making them out with sufficient certainty ; consequently we have 

 been able to speak with more confidence than we should have 

 otherwise done. The large irregularly -formed organ in Aciceon, 

 which is designated testis, is undoubtedly the same that we con- 

 sider the mucous gland. The opening of the gland externally, 

 and the detection of eggs in the anterior portion of it and in its 

 channel, are sufficient to prove that this cannot be the male 

 secreting organ. If then this be the mucous gland in Actaon, 

 the testis must be sought for elsewhere. It seems to have escaped 

 notice. The vas deferens, however, has been traced backwards 

 until it bifurcates near the median line of the body in the same 

 way as it does in Limapontia. Here, therefore, judging from 

 analogy, the testis begins ; and it will probably be found occu- 

 pying a position in the neighbourhood of the ovary. The oval 

 pouch (ij) is most likely the homologue of the dilated portion of 

 the common oviduct, and the small tube that passes from it 

 backwards, dividing dichotomously, will prove, very probably, to 

 lead from the ovarium. The oval body (a?), we would surmise, 

 corresponds with the dilated portion of the copulatory channel at 

 the base of the spermatheca ; like it, it is in communication with 

 the vas deferens, or testis, and with the oviduct ; and, if this con- 

 jecture be correct, it will also communicate with the oval sac 

 which we take to be the spermatheca : it will likewise have an 

 external outlet. 



From the description we have given of the reproductive system 

 of Limapontia, it is evident that it does not differ in any material 

 degree from what has been observed in the Nudibranchs. 



The ovary and testis are certainly considerably modified, and 

 are differently arranged in the body ; their ducts, however, and 

 the duct from the spermatheca, as in Eolis, are all brought 



