110 DR. EMBLETON ON 



different individuals, but has the same projecting valve-like free 

 edge at its cessation towards the right end of stomach, and the 

 pylorus more strongly marked than in the other species. Liver 

 has same divisions, there is the same want of gall bladder, and 

 the ductus hepaticus opens into duodenum, about 2 inches below 

 pylorus. Pancreas, sjyleen, kidneys, and supra-renal bodies like 

 those in the the other rat. 



The small intestine is 4 feet 8 inches long, coecum 3 inches, 

 large intestine 7f inches. Total length, therefore, of alimentary 

 canal about 5 feet 6 inches, against 4 feet in the black rat. The 

 coecum of the brown rat is less capacious than that of the other 

 rat, shorter and less curved; the small intestine longer, and the 

 large intestine shorter. The valvular folds of the colon are from 

 24 to 36 pairs in the brown rat, about 24 in the black, but their 

 number seems to vary, and to increase with the size of the animal. 



The female genitalia are similar in the two species. The male 

 parts in both species, as in other Rodentia, are very complicated, 

 but there are differences of detail peculiar to each species of rat. 



EXPLANATION OF PLATES I. and II. 

 EiG. I. — Stomach of Black Eat. 



— II. — Coecum, &c., of ditto. 



— III. — Stomacli of Brown Rat, 



— IV. — Coecum, &c., of ditto. 



IV. — On the short Simfish, (Orthragoriscus Mola.J — By Dennis 

 Embleton, Esq., M.D. 



[Read, Thursday, April 4th, 1850.] 

 From Pliny, we learn that the Sunfish was known to the 

 ancients by the name of pig; he says " Apion maximum piscium 

 tradit esse porcum, quem Laced^emonii Orthragoriscum vocant : 

 grunnire eum, cum capiatur." Young pigs were called in Sparta, 

 c^d^ccyo^io-Kovg, (from 'o^6^og tempus matutinum, and 'uyo^u^a 



