49 
June 8, 1841. 
William Yarrell, Esq., Vice-President, in the Chair. 
The following paper, ‘On the Blood-corpuscles of Marsupial 
Animals,” by George Gulliver, Esq., F.R.S., was read. 
«« As far as I have had an opportunity of observing, the blood-cor- 
puscles of marsupial animals possess the common circular form, and, 
compared with the red particles of other Mammals, are of rather 
large size, being nearly allied in this respect to the corpuscles of 
Man and the Quadrumana, and slightly thicker than the corpuscles 
of the Quadrumana and those of the human subject. 
“Tt is remarkable that the corpuscles of two carnivorous Marsupiata 
should differ as much in size as the corpuscles of any other two 
species of the order. This fact, however, would appear to be not 
altogether devoid of interest, for the corpuscles of different families 
of the placental Carnivora also exhibit great diversity of magnitude, 
as may he seen by reference to the ‘ Observations on the Blood- 
corpuscles of the Order Fera,’ in the Proceedings of the Zoological 
Society, May 25, 1841. Now the corpuscles of the Ursine Dasyure 
are of large size, like those of the Canide, and the corpuscles of the 
Viverrine Dasyure are considerably smaller, like those of the Felide 
and Viverride. Hence it would be interesting to inquire whether 
the blood-corpuscles of the different tribes of marsupial animals do 
not generally present the same characters as the corpuscles of the 
corresponding types of the placental series. But the few observa- 
tions which I have been able to make on the blood of the former 
order are by no means sufficient to admit of generalization. It may 
be noticed, however, that the corpuscles of an insectivorous species, 
the Perameles, are nearly as small as those of the Viverrine Dasyure, 
and that the corpuscles of the Wombat are of much larger size. 
«< The measurements which I have made, as opportunities occurred, 
of the blood-discs of the Marsupiata are here for the first time re- 
vised, arranged together, and extended by some new observations. 
The averages, which I had not previously estimated, are also now 
given; these are set down at the bottom, beneath the lines; the 
two measurements immediately above the latter indicate the sizes 
of the large and the small corpuscles, and all the other numbers were 
obtained from the common-sized discs. As usual, the measurements 
are all given in fractions of an English inch. 
« Measurements of the Blood-corpuscles of Marsupial Animals. 
« 1, Virginian Opossum (Didelphis Virginiana, Temm.). 
1°3600 Z 
13530 ( Common sizes. 
1:4570 small size. Thickness of discs. 
1-2900 large size. 1:12,000 
1:3557 Average. 
Nos. Cl. & CII.—Procrrpines oF THE ZooL. Soc. 
