TELEOSATJRID^:. 91 



Hyposaurus derbianus, Cope 1 . 



Twenty lower teeth ; mandibular rami compressed ; splenial ex- 

 tending as far forwards as the fourth tooth from the commencement 

 of the symphysis ; tweoty alveoli in the symphysis. 



Hob. South America (Brazil). 



R. 86, 305. A series of teeth ; from the Lower Cretaceous of Olaria 

 Station, Bahia, Brazil. Some of these specimens agree in 

 size with the typical examples from Pernambuco described 

 by Cope, while others are much larger. Both the com- 

 pressed and rounded types are exhibited, similar to those 

 of the corresponding teeth of H. rodgersi, figured by Leidy 

 in the ' Smith. Contrib. Knowl/ vol. xiv. pi. iii. 



Presented by Joseph Maivson, Esq., 1881-82. 



Family TELEOSAURID^E. 



Orbit separated from infratemporal fossa, aud smaller than the 

 supratemporal fossa, which may be of enormous size ; a preorbital 

 vacuity ; on the palate the premaxillae interpenetrated by the 

 maxillae. Dorsal scutes rounded, and arranged in two rows ; and 

 the ventral buckler divided, with the scutes posteriorly suturally 

 united. Marine. 



Subfamily Metriorhynchin^e 2 . 



Skull short or moderately long, with the teeth stout, and not 

 very numerous; and the orbits completely lateral, irregular, and 

 only visible as triangular notches from the frontal aspect. Anterior 

 nares heart-shaped and directed frontally ; nasals large, broad, and 

 either reaching the premaxillaB, or separated from them by a short 

 interval ; premaxillaB elongated, with a slight or no terminal 

 expansion and three dental alveoli. Palatal aspect of maxillae and 

 mandible either flat or channelled ; lachrymals invisible externally ; 

 frontals and prefrontals very large ; and palato -pterygoid vacuities 

 extensive. 



1 Proc. Amer. Phil. Soc. vol. xxiii. p. 15 (1886). 



2 There may be a question whether the term Steneosaurus was not originally 

 intended to apply to the members of this group (see Hulke, Proc. Geol. Soc. 

 1884, p. 46), but however this may have been, it is advisable to follow the 

 nomenclature employed by Deslongchamps. 



