EXTINCT BATRACHIA. 407 



COLOSTEUS SCUTELLATUS, Newb. 



Cope; Proceed. Amer, Philos. Soc, 1871, p. 41. 



Pycjoplerus scuiellatus, Newberry ; Proc. Acad. Nat. Sci., Philada., 1856, p. 98. 



Colosteus crassiscutatus, Cope; Ti-ansac. Amer. Philos. Soc, XIV., 23. 



One of the specimens of this species consists of a supero-lateral view of 

 a crushed cranium and anterior part of the body. The median pectoral 

 bone appears as a sagittiform plate, with thin edges, rounded lateral an- 

 gles, and a thin median prolongation behind. The greater part of the 

 borders of the right orbit are distinct, and display the continuity of the 

 malar and supratemporal regions. The ramus mandibuli is longer than 

 the cranium proper. The number of the teeth can not be determined, 

 but they are rather large, and traces of their existence do not extend 

 behind the orbits. The length of the long anterior mandibular tooth is 

 .005 m., and the diameter at the base .001 m. Diameter of base of a 

 superior maxillary, .002 m. The approximate length of the mandibular 

 ramus is .0715 m. ; longitudinal diameter of the orbit, .0072 m. ; length 

 of median pectoral plate, .036 m. ; width of same, .019 m. 



The sculpture of the pectoral shield is strong, and extends to the 

 edges ; the middle of the median plate is almost smooth. The lateral 

 plates are nearly right-angled triangles, with the anterior angle much 

 prolonged. 



Other specimens (Nos. 4 and 10, collection of J. S. Newberry) show 

 that the abdominal scutellation commences immediately behind the 

 pectoral bones. Those near the median line are similar to the external, 

 and their junction forms a zigzag line. The depth of these scales is 

 oblique, and is somewhat greater than the width. Thus one angle pro- 

 jects, and gives the surface an angularly ribbed rather than continuous 

 character. The following measurements express their dimensions rela- 

 tive to other parts of the body : 



Width of median pectoral, 0.0138 m. ; width of three pectorals re- 

 stored, .054; width of scale band of belly, .064; length of ulna and ra- 

 dius, .0108; length of metacarpus, .006. Scales in .01 m., transverse 

 measurement, 5.2; scales in .01 m., longitudinally on rows, 1.75. Radii 

 of lateral pectoral crossing, .01 m., seven. 



The measurements express the small size and weakness of the fore- 

 limb. Another specimen (No. 18), in which the impressions of the 

 scales are of the same size as in the preceding specimen, the impres- 

 sions of what may be femur, and ulna, and radius, are visible, which are 



