LIFE Oe ALBANY HANCOCK. XXI 



duly the value of the work detailed in this memoir, it became 



/ 



necessary that the anatomy of the mollusk concerned should 

 be investigated, and as I was at that time Lecturer on Ana- 

 tomy and Physiology in the Newcastle School of Medicine, 

 and was acquainted with Mr. Hancock's desires and difficul- 

 ties, he requested me to join him in the investigation. 



A few observations had already been made by Messrs. Alder 

 and Hancock, and the latter had, with his usual acumen, 

 detected some errors in the description of M. de Quatrefages. 

 (See "Remarks on the Grenus Eolidina, Quatrefages/' in 

 Ann. and Mag. Nat. Hist., XIV, 1844.) 



M. de Quatrefages had stated that Eolidina possessed a 

 heart and arteries, but no veins ; that, therefore, the circu- 

 lating apparatus was incomplete, the blood flowing to the 

 heart through a series of open spaces in the areolar tissue 

 of the body ; that the mouth had no teeth ; that the alimen- 

 tary canal passing down the median line of the body ended 

 in a dorsal anus, whilst there were given off on each side a 

 symmetrical series of branches, equalling- in number the 

 dorsal pupilhe, to each of which an offset was given, after 

 which the branches ended in a narrow marginal canal 

 running all round the body. 



M. Milne Edwards had, in 1842, declared the existence of 

 a similar appearance in Calliopoea, and had named it "a 

 gastro-vascular system," believing that the digestive system, 

 by its complexity, replaced in that animal the venous parts 

 of the circulating system, and also the organs of respiration. 



On dissecting in 1844 an Eolis, or Eolidina, taken at 

 Cullercoats, we found that veins as well as arteries were 

 present; that the mouth contained a spiny tongue ; that the 

 alimentary canal ended on the right side of the body, and 

 that there was no marginal canal with Avhich the branches 

 from the stomach could communicate; that the branchial 

 papillfe were the respiratory organs; that, therefore, the 

 functions of digestion, circulation, and respiration, far from 

 being' performed by one system only (a gastro-vascular), had 

 each its own special organ. 



M. de Quatrefages, in 1844, communicated to the ' Annales 

 des Sciences Natnrelles/ ser. 3, Vol. I, p. 129, another 

 memoir, in which he attempted, on the strength of his own 

 previous observations and those of Milne Edwards, to estab- 

 lish a new order of Mollusks, to be called Gasteropoda Phle- 

 benterata. In this memoir he stated that six genera of Mollusks 

 possess a gastro-vascular system, and that, in fact, the three 

 great functions of life circulation, respiration, and diges- 

 tion are performed in them by one system only, thus degrad- 



