ANATOMY OF THE EOLIS. Ill 



least a sixth of the whole animal. This was another 

 fortunate circumstance, enabling me to detect the pas- 

 sao-e of the dark o-ranules which almost filled the cav- 

 ities, to and fro from the intestine, with which these 

 cavities were in dii^ect communication. All doubt was 

 impossible : there was the food oscillating from the 

 intestine into the papillae, and back from the papillse 

 into the intestine ; and this oscillation, I observed, did 

 in nowise depend on the contractions and expansions 

 of the papillae, but wholly on the contractions and ex- 

 pansions of the body ; for sometimes the grannies ran 

 up into the cavities when the papillae expanded, but 

 sometimes they remained in their previous position. 



You see that the papillae are gastro-hepatic organs, 

 or, to speak less technically, that they are parts of the 

 intestinal and biliary apparatus ; but you see nothing 

 to warrant the accepted notion that they are respiratory 

 organs. I certainly saw nothing of the kind. It was 

 a doubt which early forced itself upon me. Zoologists 

 class the Eolis among Nudibranchiates, but I could 

 detect nothing like a gill in these said naked-gilled 

 molluscs ; and a series of dissections served to trans- 

 form doubt into a conviction, and satisfactorily proved 

 the term " branchial papillae" to be altogether erro- 

 neous. These papillae have neither the specific struc- 

 ture, nor the anatomical connection of gills. Various 

 as gills are, they have uniformly a system of vessels 

 carrying the blood to them for aeration, and a system 

 of vessels carrying the aerated blood from them. Have 

 the papillae of the Eolis such vessels ? Nothing of the 



