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 g-oVo*^ °^ ^^ ^^^^ ^^ 

 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 weight 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 would 

 communicate at some future opportunity. 



Prof.Owen next exhibited the skull of a Wombat (Phascolomys Vom- 

 hatus, 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 Phase. 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 Phase, 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 

 Tipper 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 fossae 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 Phase, latifrons is the supra- tympanic cell excavated be- 

 neath the base of the zygoma: this cell, in Phase. Vombatus, is 

 transversely oblong, simple, one inch by half an inch in size ; in 

 Phase, 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 



