156 Anatomy of Doris. 



Anatomy of Doris. 



A paper was read in the Royal Society on March 4, 1852, 

 entitled, " On the Anatomy of Doris." By Albany Han- 

 cock, Esq., and Dermis Embleton, M.D., Lecturer on Ana- 

 tomy and Physiology in the Newcastle-on-Tyne College of 

 Medicine in connection with the University of Durham. 



The authors have proposed to themselves to describe the 

 anatomy of the three genera typical of the three groups of 

 the Nudibranchiate Mollusca. An account of the structure 

 of Eolis has already appeared in the Annals of Natural His- 

 tory. 



A detailed description is given of the anatomy of Doris, 

 the following species of which have been examined, and are 

 referred to in the paper : D. tuberculala, Auct. ; D. tubercu- 

 lata, Verany ; D. Johnstoni ; D. tomentosa ; D. repanda ; D. 

 coccinea ; D. verrucosa ; D. pilosa ; D. bilamellata ; D. aspera ; 

 and D. depressa ; but D. tuber culata of English authors has 

 been taken as the type of the genera, and the standard of 

 comparison for the rest. 



Digestive System. — The mouth, in all the species, is a 

 powerful muscular organ, provided with a prehensile tongue 

 beset with silicious spines, which, when the tongue is fully 

 developed, are arranged in a median and two lateral series. 

 Certain species possess, besides, a prehensile spinous collar 

 on the buccal lip, occasionally associated with a rudimentary 

 horny jaw. The mode of development of the lingual spines 

 is shewn to be the same as that of the teeth of the vertebrata. 



The oesophagus varies in length ; in some, it is dilated at 

 the top, forming a crop ; in others, it is simply enlarged 

 previously to entering the liver mass. The stomach is of 

 two forms ; one, as in D. tuberculata, is very large, receiving 

 the oesophagus behind, and giving off the intestine in front, 

 and lying in advance of the liver ; the other is received 

 within the mass of the liver, and is very small. The liver 

 in all is bulky, mostly bilobed, and variously coloured, and 

 pours its secretion by one or more very wide ducts into the 



