422 PEOCEEDINGS OE THE GEOLOGICAL SOCIETY. [Jlllie 18, 



collectors to the various aspects under which the higher Crustacea 

 make their appearance in the oldest rocks at present known to con- 

 tain them, that I venture to communicate the present notice to the 

 Geological Society. 



4. On the Peemolae Teeth of Dipeotodoi^, and on a !N"ew Species of 



that Genus. By Thomas H. Huxley, Esq., F.E.S., Sec. G. S., &c, 



[Plate XXI.] 



A SHOET time since, I was requested by Dr. Cotton, F.G.S., to 

 examine a series of Australian fossils in his collection, which were 

 procured by Mr. Isaacs from Gowrie, in the district of the Darling 

 Downs in Queensland, the same locality from which other specimens 

 in the Hunterian and British Museums were obtained. These fossils 

 consisted of numerous teeth and fragments of jaws of Macropus 

 Atlas and M. Titan ; part of the upper jaw of a new species of 

 Kangaroo, as large as these, but allied to Lagorchestes and Hypsi- 

 prymnus ; with three lumbar vertebrae, a sacrum, portions of two 

 innominate bones, three ossa calcis, and a right metatarsal of the 

 great toe, belonging to these Marsupials. The metatarsal is remark- 

 able for its short and stout proportions. But the most interesting 

 among these remains were fragments of Diprotodon, comprising 

 sundiy molar teeth, a small portion of the right ramus of a lower 

 jaw, and parts of the right and left upper jaws of two distinct 

 individuals. Of these upper jaws, the former, which I shall call No. 1 

 (PI. XXT. fig. 1), contained the premolar in place and the socket of 

 the succeeding molar, with one fang in place. Fortunately, among 

 the detached teeth, I found the crown and principal fang of this molar, 

 and the premolar of the other side of the same skull. The other or 

 left upper jaw, No. 2 (fig. 4), has a very different colour and texture, 

 from the nature of the ferruginous matrix in which it has been im- 

 bedded. It retains a part of the palatine plate, and holds three teeth — 

 the premolar and first and second molars. What (from its aspect and 

 mineral condition) I do not doubt to be the fourth, or hindermost, 

 molar of the same series was found loose among the other teeth. 



The genus Diprotodon was founded by Professor Owen* upon 

 part of a lower jaw, collected by Sir Thomas Mitchell, from a cave 

 in the Wellington Yalley. In 1845 further details were given by 

 the same authorf, who described two fragments of lower jaws, and 

 all the lower series of teeth but the premolar. Of this tooth all 

 that is said is, " its socket shows that it was implanted, like the other 

 molars, by two fangs " (I. c. p. 214). A dorsal vertebra and a cal- 

 caneum, from the same deposits, are provisionally ascribed to the same 

 genus. 



* Mitchell's ' Three Expeditions into the Interior of Eastern Australia,' 

 vol. ii. p. 368, pi. 9. fig. 1. 1838. 



t Eeport of the Meeting of the British Association for 1844, p. 223 ; ' Ee- 

 port on the Extinct Mammals of Australia, &c,,' by Prof. Owen, F.E.S. 



