196 Dr. C. Collins-wood on the Nudibranchiate Mollusca 



grooves extending to the edge of the foot, these grooves being 

 opposite to each other at their origin. 



As I believe the animal has not yet had a name applied 

 to it, I would suggest that it should be called, in recollection 

 of the island where it was first discovered, and also of its first 

 discoverer, Aneitea Macdonaldii ; and the observations above 

 given will form its generic character. In other characters it 

 agrees with Limax. 



I may add that the description and figures of the tongue and 

 teeth ofJanella given in the interesting paper of Mr. Knight show 

 that Janella forms a most distinct family of terrestrial Mollusks. 



Mr. Knight observes that he has termed the covering of the 

 whole upper surface of Janella "the mantle," in deference to my 

 views ; but he thinks that it ought "more probably to be regarded 

 as quite naked." The study of the genus Aneitea and the exa- 

 mination of Mr. Knight's paper have induced me to change my 

 views. I now believe that the mantle is confined to the upper 

 surface of the small respiratory cavity of both these animals ; 

 and this is confirmed by Mr. Knight having discovered " four 

 small semitransparent calcareous (?) granules in the anterior 

 wall of the pulmonary sac," showing that this part must be a 

 "secretory organ;" but I do not understand how animals 

 having such plates can be " regarded as quite naked." 



XXIX. — On the Nudibranchiate Mollusca inhabiting the Estuary 

 of the Dee. By Cuthbert Collingwood, M.B., F.L.S. &c* 



In a former paper I described the species of Nudibranchiata 

 which up to that time had become known to me as inhabiting 

 the estuary of the Mersey ; I propose in the present communi- 

 cation to make some remarks upon those which are found in the 

 neighbouring estuary of the Dee. I will not here dwell upon 

 the species which are common to both rivers, having already 

 made special reference to them as existing in the Mersey, while 

 the table at the end of this article will sufficiently indicate their 

 comparative rarity or profusion in both situations. The Mersey 

 species which have not hitherto been detected in the Dee are 

 Embletonia pallida, peculiar to the Mersey, and Eolis concinna 

 and E. despecta. Of these, Embletonia has not been taken for some 

 years ; and it is to be feared that the locality in which Mr. Price 

 first discovered it has been destroyed by the formation of the 

 Birkenhead Docks. During the past spring, I have found a 

 third small species of Eolis in the Mersey at Egremont, in com- 



* Communicated by the author, having been read before the British 

 Association at its Meeting at Oxford (1860). 



