Cope.] It) [April 17, 



Deslongchamps. The palatal foramina extend forwards to the line of the 

 posterior maxillary teeth, and the anterior border is rounded, not acute as in 

 most of the species of the family.* The specimens are not sufficiently com- 

 plete to enable me to state postively the generic distinction from Steneo- 

 saurus. In Teleosaurus the vertebral hypapophyses only appear on the 

 first and second dorsal vertebra, while, as Owen observes,! they are pres- 

 ent on many of the dorsals in Hyposaurus. This peculiarity, and the great 

 contraction of the frontal bone, render it very probable that the genus is 

 distinct from Steneosaurus, but the diagnostic character yet remains to be 

 discovered. 



The Brazilian Hyposaurus is represented in the collection of the Museo 

 Nacional, by the left malar and quadratojugal bones ; by a nearly entire 

 lower jaw ; by several vertebra? from the middle and posterior parts of the 

 column ; by a humerus ; a coracoid bone ; and by several dermal bones, 

 all belonging to one individual. There are several isolated teeth of the 

 same animal, and others which probably belong to the same species, as they 

 closely resemble those which are contained in the lower jaw mentioned. 



The mandibular rami early unite into a long slender symphyseal por- 

 tion. There are twenty alveoli in each, and only five of these are in the 

 portion of the ramus which is posterior to the symphysis. The free por- 

 tion of the ramus is compressed ; both of them are broken off from the coro- 

 noid region, inclusive, posteriorly. The symphyseal region has a semi- 

 circular section, which is a little angulate ; that is, is flattened laterally and 

 below. The splenial bones appear on the inferior surface as far anteriorly 

 as opposite to the fourth tooth from the beginning of the symphysis. The 

 teeth have a lenticular section in the posterior part of the series, and the 

 section becomes rounder, that of the first pair being entirely round. All 

 display a more or less distinct cutting edge in front, and one opposite to 

 it on the posterior face of the crown. The enamel surface is marked with 

 rather close, straight, longitudinal ridges on the internal side of the crown. 

 The middle of the external side is quite smooth. The crowns are acute at 

 the apex and slightly recurved. Those of the more posterior teeth are 

 shorter, becoming little higher than wide anteroposteriorly. 



Measurements of Ramus and Teeth. M. 



Length of symphysis 336 



Width at posterior end of symphysis 075 



Depth " " " 037 



( transverse 037 



Diameters symphysis at middle j vertical ^, [[.... .., .030 



f tr&nsvcrsG • ••• .043 



Diameters at second pair of teeth \ vert j ca i 021 



* These comparisons are rendered possible by the admirable monograph of 

 these reptiles by M. Eudes Deslongchamps in Vol. x, Bulletin Soc. LinnCenne 

 de Normandie, 1866. 



t Quarterly Journal, Qeol. Society, London, 1849, p. 383. 



