AND AYES OF NOKTH AMERICA. 



197 



Germain: a series of dorsals of a, larger animal from the same locality: a, series of five consecutive lumbo-sacrals from 

 Birmingham, N. J., in the museum of the Mount Holly Lyceum, and others of the same in my cabinet, from 

 Barnesboro. 



The depressed oentra and flattened transverse oval of the articular faoes of the vertebrae, in the cervical, dorsal, 

 and lumbo-saoral series, distinguishes it at onpe from the M. maximus, M. dekayi, and the European speoles. No 

 caudal vertebra are preserved, so that their form is not known, but, it is probably discoid or rounded, as in M. missu- 

 riensis. The character is imperfectly seen by comparing the figures on Plate VII of Leidy's Cretaoeous Reptiles. 

 Figs. I) to 14 represent M. dekayi, while 2, 3 and 8 belong to the M. depressus. The vertebra more nearlj 

 resemble those of Plateoarpus tympaniticus. The Latter differs distinctly as follows: the ball is smaller in proportion 

 to the length of the vertebra, and is less transverse; in one oervical, and one dorsal it has a, more oblique uplook- the 

 base of the cervical hypapophyses is oarried to the edge of the oup as a narrow keel: in M. depressus as an elevated 

 rounded rib, as wide as the process itself. 



The remains preserved indicate an animal of less size than the M. dekayi; perhaps they point to a bulk more like 

 that of the Liodon validus. 



Inches. 

 Length of centrum anterior dorsal, gg 



Width cup, 2 3 



Depth " 2. 



Extent diapophyses, g g 



Length of live lumbo-Saorals of a, smaller individual, 13.5 



The lumbo-sacrals resemble in some degree those of M". brumbyi, but differ in important features. In the latter 

 the basis of the diapophysis is carried as a. prominent obtuse ridge, to the edge of flic ball and rim of the cup, giving 

 the centrum a, sublenticular section. In iVi. depressus these vertebra have an oval section, as the diapophysis is not 

 continued into the basal ridge, but the cup and ball are well separated from it. Some of the vertebra figured by 

 Gibbes as typical of M. brumbyi, present an obliquity of flic articular faces not characteristic of M. depressus; the 

 feature is slightly marked in specimens from Alabama,, in the writer's collection. 



Measurements of a lumbo-sacral from Barnesboro; 



Length centrum, 

 Transverse diameter cup, 



Vertical diameter cup, 



No teeth can be certainly ascribed to this species. The quadrate bone is of peculiar form, and distinguishes the 

 species from all others as readily as the vertebra. The superior or proximal extremity of this bone is characterized 

 by its relative narrowness, and Its long continuation on the upper margin of the great ala. The external angle is 

 weaker than in any other species. The ala, is strongly convex, not Battened as in the M. maximus; it is less abrubtly 

 given off from the! main shaft. The greatest peculiarity of the bone is a, ma.ssivo external longitudinal rib, just in 

 front of the, meatus, which throws the pit as if were into the mouth of the meatus, the position of the latter thus dif- 

 fering much from its usual superficial one. The rib sinks to the surrounding level just above the meatus, and is not 

 continued to the external proximal angle as in the Liodon validus, the only known species where such a development 

 of the rib exists. 



In. 



Lin. 



1 



9.5 



3 





1 



7.5 



Thickness at meatus, 



Meatus to anterior end proximal articulation, 



Greatest width proximal articulation, 



Linen. 

 16.5 



25. (i 

 12. 



Two opisthotic bones are described Under the head of Liodon validus, which it is just possible shoud be ascribed 

 to the present species. It must be added, that when the caudal vertebra are discovered they must be compared with 

 that, on which Morton founded his M. occideufalis. (See under M. dekayi.) 



I have not seen this species from any other region than New Jersey, where it is abundant. 



AMEEIOA. PHILO. SOC VOL. XIV. f>0 



