110 
very careful search might occasionally detect one or two with slight 
gibbosity of the surfaces opposite to the nucleus. 
March 24, 1842.—Viper (Coluber Berus, Linn.). 
L.D. SD. 
1-1333 1-1777 
1-1500 1-2400 
1-1067 1-1455 
1-1274 1-1800 
Nuclei, exposed by acetic acid. 
L.D. 8.D 
1-3355 1-5333 
1-3000 1-4800 
1-4000 1-6400 
1-2666 1-4000 
1-3227 1-4986 
“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 Crocodilide 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 acutus and in Champsa fissipes the corpuscles 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 nyctea), for example, are singu- 
* In an alligator, the species of which was not determined, I found the 
blood-corpuscles of the same shape. ‘The animal came from Tampico Bay, 
Vera Cruz, and died at the gardens of the Society in the beginning of Oc- 
tober 1842, 
