STENEOSAUEUS DUEOBEIVENSIS. 125 



twelve dorsals (text-fig. 37), two lumbars, two sacrals (PI. VI. fig. 6), and thirty-eight 

 caudals (text-figs. 38, A, B, C), cervical ribs (text-fig. 39), dorsal ribs, chevrons, 

 scapulas, and coracoids (text-fig. 41, A), humeri, radii, and ulnas (text-fig. 42), pubes, 

 ischia, ilia, femora, tibiss, fibulas, and many bones of hind foot ; numerous scutes 

 (PI. VI. figs. 4, 5) (R. 3701). 



In March, 1909, the present writer described this species, basing the description 

 upon the skull referred to above. Almost simultaneously, Auer published (loc. 

 cit. supra) an account of a closely similar specimen in the collection of Tiibingen 

 University, and referred it to a new variety of Steneosaurus larteti of Deslongchamps. 

 As it seems certain that this species is distinct from St. larteti, and as, moreover, the 

 greater part of the available specimens are in the British Museum, the name Steneo- 

 saurus durobrivensis is here employed. 



In this species the rostrum (PI. VI. figs. 1, 2) is of moderate length only, the 

 preorbital region being about 61 per cent, of the whole, while in St. leedsi it is about 

 73 per cent. The temporal fossae are very large and about twice as long as wide ; the 

 orbits are proportionately smaller than in St. leedsi. The frontals terminate anteriorly 

 in a very obtuse augle a little in front of the level of the anterior rim of the orbits. 

 In the type specimen the bone is coated with a pyritous incrustation concealing 

 the sculpture, which, judging from another specimen (R. 2865), consists of irregular 

 pits on the frontals and prefrontals, and numerous more or less longitudinal grooves of 

 varying length on the surface of the rostrum. In the upper jaw there are about 

 thirty-four teeth on each side, of which thirty are borne on the maxilla ; the anterior 

 point of the nasals is about opposite the sixteenth maxillary tooth, while the anterior 

 angle of the palatines is about opposite the twenty-second, so far as can be made out. 

 A number of detached teeth (PL V. fig. 5 ; PI. VI. fig. 3) said to be associated with 

 the type skeleton are very sharply pointed, having the crowns covered with finely 

 ridged enamel on their lower part, Avhile the summit is smooth, somewhat compressed, 

 and with two well-marked carinse on opposite sides; there are also some teeth with 

 blunter points having the enamel-sculpture extending to the tips and very slightly 

 marked carinas. Teeth of a similar character to these last are seen just showing their 

 tips in the lower jaw of the type. It is doubtful whether both these forms of teeth 

 belong to this species, differing in different parts of the jaw. 



In the mandible there are about thirty-one teeth on each side ; the posterior end of 

 the symphysis is opposite the twenty-fifth, the anterior angle of the splenials opposite 

 the seventeenth. The symphysial region of the mandible occupies about 44 per cent, 

 of its total length. 



As has been noted above, in correlation with the shortness of the head, the vertebras 

 and the bones of the limb-girdles are relatively shorter than in the long and slender 

 skulled St. leedsi. The scutes seem to have larger and shallower pits than in St. leedsi, 

 and these do not show the tendency to elongation and arrangement in lines running 



