12 FOSSIL REPTILIA OF THE 



below the level of the sculptured surface of the mastoid, and which becomes smooth like 

 the contiguous and lower-placed tympanic. This character, shown in the subject of 

 fig. 3, PI. Ill, usefully indicated fragmentary parts of the skull of other individuals of the 

 species, such as are figured in fig. 1, 13', PI. IV. The supra-temporal vacuities are relatively 

 larger than in Nannosuchus. The intervening tract of the parietal, rather more canaliculate 

 than in Nannosuchus, is divided by a mid ridge in two of the cranial specimens, and 

 partially so in the more complete skull. 



No palpebral ossicle is preserved in the orbit (o). The pointed ends of the nasals are 

 produced so as to divide the outer nostril into two, as in some specimens of Crocodilus 

 niger ; were this a character of generic value, it might unite Theriosuc/ms with Halcrosia, 

 Gray.^ 



The alveolar part of the maxillary in which the canines are developed make a 

 corresponding convex extension of its outer border, as in Goniopholis. 



The extent of the ' symphysis mandibulse ' and the angle of divarication of the 

 rami are shown in fig. 4, PL III. 



The matrix was removed as far as practicable from the palatal surface of the skull 

 (fig. 4) and exposed a portion of the basisphenoid (5), of the pterygoids (24), of the 

 palatines (20), and palatal plates of the maxillary (2') ; the ptery go-maxillary vacuities [y) 

 and the hind portion of the palatonares {n) were brought into view. What seems to be 

 a portion of the hind part of a mandibular ramus was so wedged down upon a part of 

 the palatal surface that, in regard to the fragile character of this unique skull, it was 

 deemed unadvisable to attempt its removal. 



In PI. IV a portion of the skeleton of Tkeriosuchus pusillus is figured. It is of one 

 individual. In the slab of matrix in which it is imbedded the fore part, marked a, a, is 

 continued on from the hind part with an interval of the extent marked b. At this 

 interval the slab has been broken across, but the parts appear to have been naturally 

 readjusted before the specimen was fixed in its present frame. The position in which 

 the two portions of the skeleton are figured relates to the convenience of size of the 

 Plate. 



The skull has been displaced and fractured, but the contiguity of the preserved portion 

 with the vertebral column supports the conclusion that it formed part of the skeleton of 

 the same individual. It thus serves to determine the species to which the subject of 

 Plate IV belonged. 



The part of the skull includes the parieto-mastoid platform (/". 12') with the tympanic 

 (28) and the squamosal (27). The articular surface of the tympanic for the mandible shows 

 the Crocodilian character. The median or sagittal ridge of the parietal is well marked, 

 and is continued along the raid-frontal. This character is partially effaced by mutilation 

 in the more entire skull (PI. Ill, fig. 3). It is well shown in the frontal bone indicating 

 the largest of the specimens of Theriosuchus (PI. Ill, fig. 8). 



1 ' Trans. Zool. Soc.,' vol. vi, p. 135. 



