123 



shells are marked with cross grooves resembling the grooves on the 

 shell, yct these grooves are only formed by the pressure of the dead 

 animal against the shell ; for the specimens of the animal which are 

 found out of the shell, or which are taken out of the shell while re- 

 cent, are always destitute of these grooves, or of the compressed 

 forra of the cavity of the shell. That some specimens •which he 

 had recelved from the Cape (of \vhich that now on the table was 

 one), -yvliich had been packed on their sides, had the upper side 

 of the animal smooth and rounded, and the lower flat, and curved 

 likę the shell on \vhich it was pressed by its o-wn weight ; \vhile a 

 specimen which he had rcceived from the Mediterranean packed 

 erect, vv'ith the mouth up\vards, so that the animal was equally pressed 

 against each side of the shell, was flattened and curved on each side, 

 likę the specimen examined by M. Ferussac. 



Mr. Gray also stated that, so far from the animal using the finned 

 arms as sails, they ■vvere the means by which it retained itself in the 

 shell ; and he further obsen-ed, that it was very difRcult to distin- 

 guish the species of Argonautą, as they varied greatly in shape, and 

 that on a comparlson of many specimens, he had found that the 

 presence or absence of the spines or ears at the back of the mouth 

 vi^ere of no importace as a specific character, specimens of each of 

 the recorded species having this process developed only on one or the 

 other side. 



Tlie Chairman, after premlsing some observations on the diseases 

 to ■vvhich the mortality of the larger feline animals in the Society's 

 Menagerie was attributable, proceeded to read the following descrip- 

 tion of two Entozoa infesting the stomach of the Tiger, (Felis Tir/ris, 

 Linn.,) one of which forms-the type of a new genus of Nematoidea. 



" I received a few days ago, from the Medical Superintendent of 

 the Society's Menagerie, a portion of the stomach of a young Tiger 

 (vvhich died of rup ture of the aorta), exhibiting on the internal or 

 mucous surface -vvhat were considered to be scrofulous tumours. 

 They -svėre five or six in number, of a round and oblong form, vary- 

 ing in size from half an inch to two inches in the largest diameter, 

 and the largest of them projecting abouthalf an inch from the plane 

 of the inner surface : they made no projection externallJ^ Tlie mu- 

 cous membrane covering the smaller tumours \vas puckered up into 

 minute reticulate ruga : the sui-face of the largest tumour was smooth. 

 On \viping avi'ay the tough thick mucous secretion from the tu- 

 mours, and examining more closely their surface, two or three orifices 

 prcscnted themselvcs in the larger, and a single orifice in each of the 

 smaller tumours. These orifices conducted to irregular sinuses Avliich 

 were the nidi of t\vo kinds of Nematoid Entozoa, some measuring 

 nearly an inch in length and a line in thickness; the others being 

 more minute, not exceeding 5 lines in length, and about ^L of an 

 inch in diameter. Only a pair of the larger Entozoa M-ere found in 

 each of the three largest tumours ; the smaller species existed in 

 countless uumbers. 



" 13efore procccding \vith the description of the vorms, I may 



