STENEOSAUEUS HULKEI. 123 



the species from St. edwardsi and approximates it to St. durobrivensis. The symphysis 

 of the mandible is comparatively short, about 40 per cent, of the total length ; its 

 posterior end is opposite the twenty-first tooth. The splenials run into the symphysis 

 to the level of the thirteenth tooth; in the posterior half of their symphysial region 

 they are marked off from the dentaries by a deep groove. The teeth are relatively 

 large. The skeleton, on the whole, is closely similar to that of St. durobrivensis ; in 

 the vertebrae, however, particularly in the dorsal region, the neural spines are rather 

 lower. The scutes also are different, the depressions being shallow, separated by wider 

 smooth areas of bone, and, in many cases, much elongated in a. transverse direction. 



It is a notable circumstance that none of the species of Steneosmirus from Peterborough 

 agree exactly with the species described by Deslongchamps from the north of France ; 

 this is probably due to a slight difference of geological horizon. At the same time 

 some of the differences now taken to be specific may be age-characters, for nothing is 

 known definitely as to whether changes in the proportionate length of the snout or in 

 the character and number of the teeth may take place in the course of growth. 



2074 (Leeds Coll. 2). Skull, imperfect mandible, atlas, axis, and seven other cervical vertebra?, 

 fourteen dorsals, two sacrals, and seven caudals ; a number of dorsal ribs, sacral ribs : 

 ilia, ischia, pubes ; right femur, tibia, part of fibula, numerous bones of the hind feet, 

 and many scutes. Type specimen ; the axis, a middle cervical, a dorsal, a caudal, a 

 sacral with the sacral ribs, left ilium, ischium, and pubes figured by Hulke, loc. at. 

 supra. 



Some dimensions (in centimetres) of this specimen are : — 



Skull : total length (approx.) 6O0 



length in front of the orbit ...... (approx.) 35'0 



width at outer angles of quadrates ....... 22-0 



length of temporal fossae (inner side) 15-3 



width of temporal fossas (in middle) 8"0 



„ frontals between orbits 4 - ti 



„ snout at anterior end of nasals 5- 4 



width behind the premaxillary expansion 4'7 



„ of preinaxillaiy expansion o'5 



The measures- of width are probably somewhat too great, owing to the flattening 

 that the skeleton has undergone. 



Mandible : approximate length 72 - 



length of symphysial region 2S - 9 



width at hinder end of symphysis . . (.approx.) S'O 

 ,, narrowest point behind the anterior ex- 

 pansion 3'8 



K ". 



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