132 



tiles et polssons, le petit diamfetre pour unite, le grand varie entre 

 1 5 a 2 ; on en rencontre une exception dans les Crocodiliens, dont le 

 grand diamfetre est 2 a 3 fois plus grand que le petit.' 



" It appears that this conclusion was deduced from an examination 

 of the blood of a single species only, the Crocodilus Lucius of Cuvier. 



" In a short paper ' On the Blood Corpuscles of the Snov/y Owl 

 and Passenger Pigeon,' read before the Society on the 9th of June, 

 1 840, I showed that the corpuscles of these birds, particularly of the 

 former, were so very long, in relation to their breadth, as to present 

 a peculiarity in this respect which I had not seen in the corpuscles of 

 any other vertebrate animal ; and, however singular it might appear, 

 it was shown in the same communication that the blood-discs might 

 differ remarkably in two nearly allied species of the same genus. 

 Hence it will not appear surprising that I have failed to find the same 

 peculiarity in the figure of the blood corpuscles of two other species 

 of the Crocodilidce, as M. Mandl did in the Crocodilus Lucius. In the 

 following measurements the common-sized corpuscles are first noted, 

 then those of extremely small and large dimensions, and lastly the 

 average deduced from a computation of the whole ; and they are all 

 expressed in fractional parts of an English inch. 



" 1. Sharp-nosed Crocodile {Crocodilus acutus). 

 Long Diameter. Short Diameter. 



1333 



1231 



II45J 



1600\ 



1000/ 



I Common 



sizes. 



Extremes. 



1'2286 Common size^ 

 1-26661 17 . 

 1-2000 J^''^^""^'- 



1-2286 Average. 



1-1231 Average. 



" The average thickness of the discs was about g^o^^th of an inch. 

 " The animal was young, and the blood was obtained from tlie 

 heart after death. 



"2. An AUigator from South America (Ckampsa fissipes, Natterer). 



Long Diameter. 

 11455^ 

 1333 I Common 

 1200 ^ 



1143 

 1600 

 1000/ 



sizes. 



Extremes. 



Short Diameter. 



2666T 



2400 I Common 



2286 ^ 



2000 



3000' 



1895 



sizes. 



Extremes. 



1-2315 Average. 

 The blood was obtained frofli 



ri259 Average. 



*' ITie animal was young and lively, 

 a prick of the foot. 



of the Vicugna and Guanaco, and found their corpuscles also of an oval shape, 

 thus completing the history of the singular red particles of the Camelida. 

 See 'Dublin Med. Press,' November 27, 1839, and 'Trans, of the Royal 

 Med. and Chirurgical Society,' vol. 23. 



