338 W. H. Ttcelvetrees — Permian ReptiUa of Russia. 



out to be different from that of Cynodraco. I imagined that the 

 spots visible on the surfaces of the transverse sections might be 

 vascular canals cut obliquely across in their course to the circum- 

 ference. Mr. Hulke and Prof. Seeley obligingly pointed out to me 

 that this could not be the case, because the calcigerous tubes are 

 seen to radiate from the centre horizontally, and if vaso-dentinal 

 canals existed, they must run in the same plane. 



Eichwald's Deuterosaurus hiarmicus is represented by remains from 

 the Upper Permian copper mines of Klioutschefsk in the Bielebee 

 district of the Ufa government. The skull contains teeth differen- 

 tiated into premaxillaries, canines and molars. The lower canine 

 figured in Eichwald's Leth^a Eossica, tab. Iviii. fig. 1, somewhat 

 resembles our tooth, but is more cylindrical, besides being smaller, 

 and no mention is made of any serration of the posterior border. 

 Some confusion exists in the description in consequence of taking 

 the incisors for canines. 



The present tooth does not appear to belong to any known rep- 

 tilian genus from the Eussian Permian rocks, and we must conse- 

 quently wait for the announcement of further discoveries. 



Incisor of Deuterosaurus hiarmicus. — This is shown by Fig. 2 in 

 our Plate. It is a large tooth, with the crown anteriorly elevated 

 into a point, and posteriorly bulging out into a swollen protuberance 

 superficially rugose. On the protuberance the rugee are furrowed 

 transversely. They pass up and over the top of the posterior part 

 of the crown, subsiding as they approach the acuminate summit, the 

 front and sides of which are smooth. The whole tooth, crown and 

 fang, with the exception of the posterior protuberance, is laterally 

 compressed. Blunt serrations exist along the external edge of the 

 crown, decreasing in size and number in the ascent of the summit. 

 The specimen being broken into two pieces, one can see that a pulp 

 cavity extended backwards and upwards into the post-basal pro- 

 tuberance. The dentinal structure is of the ordinary kind — tubuli 

 radiating from the central cavity. The fang is hollow and its cavity 

 is occupied by the sandstone matrix. 



Supposed Dinosaurian Tooth. — Fig. 3 is a curved sabre-like tooth, 

 the posterior trenchant edge less curved than the anterior one. A 

 fine crenation prevails all the way down this edge. The anterior 

 border is armed with a similar crenation, which ceases after pro- 

 ceeding down about three-fourths of the crown. This crenation does 

 not follow the median line, but runs parallel to it, and terminates 

 quite abruptly. The enamel is smooth, a little wrinkled here and 

 there, and marked with faint and fine longitudinal strifB. The base 

 of the tooth is hollow. Higher up, the pulp cavity exists merely as 

 a linear trace. 



The partial crenation reminds one of Megalosaurian teeth. It is 

 not a character observed in any of the teeth referred to Theriodonts, 

 and is to my mind suggestive of the existence of a Eussian Dinosaur- 

 ian reptile in Permian times. It is a thinner, more compressed tooth 

 than Megalosaurian teeth generally. 



Huxley, in his paper on the " Classification of the Dinosauria, 



