164 TROF. H. G. SEELEY OX AGR0S4URUS MACGILL1VRA.YI. 



12. On Agros.vurus Macgillivrayi (Seelei/), a Saurischian Keptile * 

 from the N.E. Coast of Australia. By Professor H. G. Seeley, 

 F.R.S., r.G.S. (Read January 21, 1891.) 



In July 1879 the Geological Department of the British Museum 

 obtained by purchase from Mr. E. Charlesworth some fossil bones, 

 which were dispersed at the sale of the collection of Mr. S. L. 

 "Waring, F.G.S., of Xorwood, then recently deceased. They are 

 labelled, in a small, delicate handwriting, " ' Fly,' 1844. Jn. Mac- 

 gillivray, from the i!^.E. coast of Australia." I believe this to 

 indicate that the specimens were collected by Mr. Macgillivray 

 during the voyage ot' the ' Fly,' from some locality which was then 

 unnamed. The bones were placed in the Mammal Gallery, where 

 they have since remained. They comprise a complete left tibia, 

 a less perfect proximal end of the corresponding right tibia, a 

 fragment which I regard as a portion of a fibula, attached to 

 matrix, which besides other fragments of bone contains two laterally 

 compressed claw-phalanges. There is necessarily no direct evidence 

 of their geological age. But as they indicate a new Saurischian 

 reptile, which has its nearest known allies in the lower Secondary 

 rocks of Euro])e and the Trias of South Africa, it is not improbable 

 that the animal belongs to the Lower Oolites or Trias. I have not 

 noticed any reference to the specimens by Professor Jukes in the 

 " Yoyage of the ' Fly ' " or in his other books and papers, or in the 

 writings of Mr. Macgillivray. 



The left tibia (figs. 1, 2) is about 20 cm. in extreme length, 

 with the usual sub- triangular flattened proximal articular surface. 

 That surface is nearly 5 cm. deep by 4 cm. wide posteriorly, and is 

 flattened on the hinder and fibular borders, which are inclined at, a 

 right angle, and convex on the antero-internal contour, so that a 

 distinct thick anterior crest is defined without obliterating the right- 

 angled triangle form. The articular surface is slightly inclined 

 towards the posterior and fibular borders, partly because there is a 

 small patelloid convexity above the pre-cnemial crest, then a trans- 

 verse concavity, behind which is the larger part of the articulation, 

 consisting of two areas which correspond to condyles. These surfaces 

 are divided by a shallow groove, and the larger condyle was on the 

 external border. The posterior angles of these condylar surfaces are 

 rounded and prolonged backward beyond the shaft, and there is a 

 slight concavity between them. 



The proximal end of the bone is expanded as compared with the 

 unusually slender sub-cylindrical shaft, which is 12 millim. in 

 diameter. The anterior internal surface, though flattened, is gently 

 convex, and it rounds into the posterior surface of the bone, as well a^ 

 on to the strong anterior convex ridge of the pre-cnemial crest, which 

 is prolonged down the shaft for about 6 cm. with a gently convex 



* See Proc. Eoy. Soc. vol. xliii. p. 165, and Quart. Journ. Geol. See, vol. xliv. 

 (1888) p. 70. 



