no SEA-SIDE STUDIES. 



the digestive apparatus, the Liver. It is useless seek- 

 ing for it ; the Eolis has not reached that stage of 

 animal development which imperiously demands a 

 special biliary organ ; it can transact all digestive re- 

 quirements by the aid of biliary vesicles scattered 

 alono: the linino^ membrane of those intestinal branches 

 which we saw filling the cavities of the papillae. In a 

 word, we here meet with the rudimentary and initial 

 condition of the liver, nothing more than a few hepatic 

 cells. 



You understand, therefore, that these papillae cover- 

 ing the back, and bristling up like quills upon the 

 fretful porcupine when the Eolis is irritated, are hol- 

 low tubes, containing prolongations of the intestine, 

 and biliary cells. By many anatomists it is thought 

 that these tubes are biliary ducts, and perhaps in some 

 species this may be so, but that it is not so in all, I have 

 positive evidence. I was one day examining some 

 Polypes, when my attention was diverted by something 

 granular, contractile, indistinguishable in shape. On 

 extricating it from the branches of the Polype, I found 

 it to be a white oblong jelly-like creature, about the 

 size of a pin's head. On placing it under the micro- 

 scope, I saw that it was an Eolis, but whether of a yet 

 undescribed species, or only the young of some known 

 species, imperfect knowledge did not enable me to 

 decide. The extreme transparency of its tissues was 

 such that I could observe it with satisfactory precision. 

 It had only eight papillae on either side, but these 

 were very large, each of the central ones measuring at 



