THE ANNALS 



AND 



MAGAZINE OF NVrURAL HISTORY, 



♦* per litora spargite museum, 



Naiades, et circilm vitreos considite fontes ; 

 PoUice virgineo teneros hic carpite flores : 

 Jloribus et pictum, divaj, replete canistrum. 

 At vos, o Nymphee Craterides, ite sub undas ; 

 Ite, recurvato variata corallia trunco 

 Vellite muscosis e rupibus, et mihi conchas 

 Ferte, Dese pelagi, et pingui conchylia succo." 



P arthenii Ec\. 1. 



No. 95. JANUARY 1845. 



I. — On the Anatomy of Eolis, a genus of MoUusks of the order 

 Nudibrancliiata. By Albany Hancock and Dennis Em- 

 BLETON, M.D.J F.R.C.S.E., Lecturer on Anatomy and Phy- 

 siology in the Newcastle-upon-Tyne School of Medicine. 



[With five Plates.] 



1 HE Nudibranchiate MoUusks are divided into two families, 

 the Doridce and the Tritoniadce ; the anatomy of the former was 

 fully investigated by Cuvier, that of the latter, however, was only 

 partially examined by that illustrious physiologist ; and the Eo- 

 lidina^, a very extensive division of it, were left totally unex- 

 plored, but were nevertheless considered to agree in organization 

 with Tritonia Homberffii, the typical form of the group. 



Recently however the attention of zoologists has been drawn 

 to the subject by M. Milne Edwards, who was the first to point 

 out that the Eolidin(B deviate in a very striking manner from the 

 rest of the family. He found in the genus Calliopaa a ramified 

 digestive apparatus. This curious organ was supposed by that 

 gentleman to perform the double function of digestion and cir- 

 culation, and consequently to have analogy with the gastro- vas- 

 cular system of the Medusidceiiyn the one hand, and on the other 

 with the Nymphon, on account of the csecal prolongations of the 

 digestive organ that penetrate the exterior branchial papillae. 

 Since this discovery there has appeared in the ' Annales des 



* We use this name to designate the subfainih' of which EvUs is the type. 

 Ann. ^ Mag. N. Hist. Vol xv ' /B 



