52 



April 24th. 

 R. C. Griffith, Esq., in the Chair. 



Some notes by Mr. Martin were read. On the visceral anatomy 

 of the Sjiotted Cavy, Cmlogenus subniger, taken from the examina- 

 tion of a male specimen which had died suddenly in the Menagerie 

 of the Society. The length of the head and body along the spine 

 measured about 1 foot 10 inches. 



On opening the abdomen, the large folds of the caecum presented 

 themselves, occupying the whole of the umbilical and epigastric re- 

 gions, while to the left appeared the coils of small intestine ; and a 

 jjortion of the stomach was seen to emerge from below the edge of 

 the left jiortion of the liver. The omentum was of very small extent, 

 destitute of fat, and crumpled up beneath the stomach. 



The duodenum commenced in the form of a large pear-shaped 

 sac, which measured in length 2f inches, when the intestine as- 

 sumed its ordinary size, namely about half an inch in diameter. The 

 dimension of the sac at its largest part was four inches in circum- 

 ference. This pyriform commencement of the duodenum obtains in 

 many Rodents, and also in some Insectivora ; among the former may 

 be noticed the Coypus, Capromys, and Ancema : in the insectivorous 

 animal lately described (Zool. Proc. 1838, p. 17.) under the name 

 of Echinops Telfairi, the same structure also is remarkable. The 

 course of the duodenum was as follows : leaving the pylorus and 

 loosely attached by mesentery, it described an arch over the 

 right kidney, whence it passed over the spine to the left kidney ; it 

 then turned back to the spine, and there making several abrupt con- 

 volutions merged into the jejummi. In the sacculated part two 

 areola of glandular follicles were apparent through the parietes. 

 As in the Agouti, (Zool. Proc. 1834, p. 82.) the stomach had a con- 

 striction between its cardiac and pyloric portion ; in which point 

 (as does the Agouti,) it differs from the Acouchi, the dissection of 

 which will be found in the Proc. of Com. of Sci. &c., 1831, p. 75. The 

 length of the stomach lying on the table undistended, or but slightly, 

 was 6 inches; the cardiac portions swelled out to the extent of nearly 

 2 inches beyond the entrance of the wsopkagus, and its pyloric ex- 

 tremity swelled out into a process on each side, as in the Agouti. 

 A muscular band, commencing at the entrance of the oesophagus, 

 passed longitudinally along the stomach, contracting the greater 

 curve into sacculi, especially at the constricted portion. The length 

 of the oesophagus within the abdomen was one inch and a quarter. 



The length of the small intestines was very great, the measure- 

 ment being 21 feet 8 inches. 



The caecum was large, irregularly , multitudinously , but not deeply 

 sacculated ; in form it was gently conical, terminating in a subacute 



