BY C. D. GILLIES AND B. B. TAYLOR. 169 



than the abnormally dilated diapophysis of the eighth. The 

 undilated diapophysis was only slightlj'^ more than half the 

 length of the latter and was directed posteriorly at an 

 angle of about 45° to the longitudinal axis. The foramina 

 of the ninth spinal nerves were sitixated at the junction of 

 the diapophyses with the urostj^lar region, the foramen 

 associated with the dilated diapophj'sis being the larger 

 and more elongated of the two. 



The dilated transverse process of the eighth and the 

 fused ninth and urostyle together formed the sacrum. 

 In the specimen described in this paper the left diapophysis 

 of the eighth and the right of the fused ninth were dilated, 

 but Gillies and Peberdy* recorded a variation in which the 

 right of the eighth and the left of the ninth were dilated, 

 also viewed from the ventral surface. Again, in the latter 

 the processes were approximately equal in size, but in our 

 speciinen the diapophj'sis of the eighth was the larger of the 

 two. 



Though jjossibh' the malformation of the second, 

 third and fourth vertebrae may have been the result of an 

 accident, this can hardly be said of eighth and the fused 

 ninth urostyle, neither of which exhibited traces of injury, 

 so we infer that the specimen examined owed some of its 

 most striking abnormalities to variation. 



*Proa Roy. Soc. Q'land, xxix, 1917, p. 53. 



