128 Zoological Society. 
The circular form of the blood-discs of the Echidna was noticed 
by Dr. John Davy in some blood of that animal which had. been 
transmitted to him in brine from Van Diemen’s Land. More satis- 
factory observations had been made by Dr. Hobson and Mr. E. Bed- 
ford, on the recent blood of both the Ornithorhynchus and Echidna. 
I have cited these observations in my article ‘ Monotremata’ (Cyclop. 
of Nat. Hist.) ; they show that the blood-discs of the Ornithorhyn- 
chus are likewise discoid, circular, and about z,),5th of an inch in 
diameter ; and the observations now made on both ovoviviparous 
genera demonstrate that the Monotremata resemble the other Mam- 
malia in the form, proportional number, and florid colour of the blood- 
discs, which correspond in size with those of the Armadillo and the 
Quadrumana, but are larger in proportion to the size and ween of 
the body than in the larger apes and the human species. 
The Echidna having died unexpectedly a short time after its ar- 
rival, has afforded a favourable opportunity of investigating certain 
obscure parts of its anatomy, the results of which Prof. Owen eran 
communicate at some future opportunity. 
Prof.Owen next exhibited the skull of a Wombat ( Phascolomys Vom- 
batus, Auct.) from Van Diemen’s Land, and the skull of a Wombat, 
transmitted by Governor Grey, from Continental (South) Australia, 
and pointed out the following differences in proof of their specific 
distinction. They are of equal size, but the skull of the specimen 
from South Australia is broader in proportion to its length. In the 
continental species, which he proposed to call Phascolomys latifrons, 
the upper incisors present a transverse semi-oval section, the convex 
enamelled surface being directed forwards and outwards. This sur- 
face is feebly striated longitudinally. ‘The lower incisors are nar- 
rower than in Phasc. Vombatus, and triedral, the enamelled anterior 
or under surface is flat, the outer surface longitudinally impressed 
and almost devoid of enamel. The first lower molar (premolar) is 
relatively larger, the last relatively smaller, in Phasc. latifrons: the 
symphysis of the jaw is narrower and deeper. The intermaxillary 
part of the skull is higher in proportion to its width, less convex 
externally ; the nasal bones are relatively broader, forming the whole 
upper surface of the anterior third of the skull. The inter-orbital 
part of the skull is relatively much broader, and is produced on 
each side into a well-marked supra-orbital ridge and post-orbital 
process, both of which are almost obsolete in Phase. Vombatus. 
The temporal fossz are not bounded, as in Phase. Vombatus, by two 
nearly parallel and remote longitudinal ridges, but are continued 
by a convex, rather irregular tract, to near the middle of the upper 
region of the cranium. A very remarkable feature in the skull 
of the Phasc. latifrons is the supra-tympanic cell excavated .be- 
neath the base of the zygoma: this cell, in Phasc. Vombatus, as 
transversely oblong, simple, one inch by half an inch in size; in 
Phasc. latifrons it extends inwards one inch and a quarter, and ex- 
pands to an antero-posterior diameter of one inch and a half, and 
a vertical diameter of one inch, having an oblong outlet one inch 
