300 TEETIAET VERTEBEATA OE THE EAYtM. 



the plastron in the groove between the humeral {n.) and pectoral (p.) shields. In some 

 specimens the upper surface of the epiplastrals is raised into a sort of boss near their 

 posterior angle, and from this a slight ridge is continued backwards to tlie axillary 

 buttress. The suture between the hyo- {Hy.p.) and hypoplastrals {Hyp.p.) crosses 

 the middle of the bridge and terminates at the inner angles of the small meso- 

 plastrals (Ms.p.), which are irregularly hexagonal in outline and are wedged in between 

 the outer ends of the hyo- and hypoplastrals and the marginals. The sutures 

 between the hypoplastrals and xiphiplastrals (Xi.p.) make an angle of about 115° 

 with the middle line, and are slightly convex forwards. The posterior border of the 

 plastron seems to have been notched in the middle line as in S. libyca, but in no 

 specimen is this region well preserved. 



The. arrangement of the horny scutes on the plastron is only known in the case of 

 the anterior region. The intergular {ig.) is very large, its posterior point being about 

 on the middle of the entoplastron. Both the gulais {g.) and humerals (n.) are verv 

 small and widely separated by the intergular. In Stereogenys podocnemioides, Reinach, 

 the humerals are much larger and their posterior angles coincide with that of the 

 intergular : this condition is transitional to Fodocnemis, in which both the gulars and 

 humerals meet in median suture behind the intergular. 



C. 10027. Skull and mandible, found actually articulated with each other. The skull is somewhiit 

 crushed and is imperfect in the premaxillary region. Many of the sutures are obscured 

 by a coating of gypsum. Type specimen described and figured in Geol. Mag. [4] 

 vol. viii. (1901) pp. 442-3, fig. 4 ; also on PI. XXV. figs. 2, 3. The dimensions (in 

 centimetres) of this specimen are : — 



Skull : 



Extreme length iu middle line 9-6 



„ „ from end of the squamosals 10-5 



Greatest width (at tympanic opening) 9'8 * 



Width between the ends of the ectopterygoid processes . . 6-5 



,, „ outer ends of quadrate articulations . . . 7'5 



,, of quadrate articulation 1-4 



Distance from internal nares to tip of nose 5 



Width of palate 4 



Mandible : 



Total length 7-1 



Length of symphysis 4-3 



Width at coronoid process 5-5 



„ articular surfaces for quadrate 6-4 



R. 3007. Plaster casts of the above specimens. Mixde in the British Museum. 



* This measurement is a little exaggerated, through the distortion due to crushing. 



