526 Zoological Society. 



1-1178 inch, S.D. = 1-2666 inch ; and of the pale globules of the 

 blood (abundant) = 1-2626 inch. 



Sept. 9, 1841. — Common Snake {Natrix torquata, Ray) : L.D. = 

 1-1371 inch; S.D. = 1-2157 inch; thickness = 1-8341 inch; nu- 

 clei, exposed by dilute acetic acid, L.D. = 1-3835 inch ; S.D. = 

 1-6817 inch; and of the pale globules of the blood (tolerably nume- 

 rous) = 1-2322 inch. 



" The pale globules were generally granular and opake, though 

 some of them were thin and transparent at the edges, as if growing 

 into discs. In the blood there were many circular discs of a deep 

 red colour, and generally 1 -2666th of an inch in diameter. The 

 regular discs were rounded at the edgee, and almost all flat; but a 

 very careful search might occasionally detect one or two with slight 

 gibbosity of the surfaces ojiposite to the nucleus. 



March 24, 1842.— Viper {Coluber Berus, Linn.) : L.D. = 1-1274 

 inch ; S.D. = 1-1800 inch ; and nuclei, exposed by acetic acid, L.D, 

 = 1-3227 inch; S.D. = 1-4986 inch, 



" The discs were clearly gibbous on the surfaces opposite to the 

 nucleus. The pale globules were very numerous, and their common 

 diameter was 1 -2666th of an inch, 



" Figure of the Corpuscles. — From the preceding measurements it 

 results, that although the blood-discs of the Viper and Snake pre- 

 sent the form of an ellipse rather less than twice as long as it is 

 broad, in the Slow Worm the elliptical figure of the discs is more 

 elongated, since its length is considerably more than twice its 

 breadth, 



" As M. Mandl states, all observers had agreed that the long dia- 

 meter of the oval blood-corpuscles of vertebrate animals was never 

 more than one and a half or twice the short diameter, when he de- 

 scribed the corpuscles of the Crocodilida as forming a singular ex- 

 ception to this rule ; because he found that the long diameter of the 

 blood-discs of Crocodilus Lucius was between two and three times as 

 much as the short diameter. I am not aware whether M. Mandl 

 had examined any other species of this family ; but, as described in 

 the 'Proceedings of the Zoological Society,' Nov. 10, 1840, I found 

 that in Crocodilus acuius and in Champsa fissipes the corijuscles had 

 the most common oval form, the length being rather less than twice 

 the breadth*. 



" In the ' Proceedings of the Zoological Society,' June 9, 1840, I 

 showed that the blood-corpuscles of some birds differ greatly in 

 figure from the corpuscles of other congenerous species. The cor- 

 puscles of the Snowy Owl {Syrnia nycted), for example, are singu- 

 larly elongated ellipses, while the corpuscles of the Common Brown 

 Owl have the usual oval form ; and a similar peculiarity, though in 

 a less degree, was observed in comparing the corpuscles of the Pas- 

 senger Pigeon (Columba migratoria) with those of other allied species. 



* In an alligator, the species of which was not determined, I found the 

 blood-corpuscles of the same sliape. The animal came from Tampico Bay, 

 Vera Cruz, and died at tlie gardens of the Society in the bcgiiming of Oc- 

 tober 1842. 



