48 REVISION OF THE PELYCOSAURIA. 



Original description : "This saurian is established on the nearly complete pre- 

 inaxillary and maxillar>' bones of the right side with the left maxillar}' of the same 

 individual. Associated with these are portions of the postfrontal, frontal, and nasal 

 bones of the right side of perhaps the same individual, but, as the pieces are loose, this 

 relation can not be positively affirmed. Portions of the maxillar}', premaxillary, and 

 other bones, with isolated teeth of numerous other individuals, are in my possession. 



"The first-named specimens show that the mutual premaxillary and premaxillo- 

 maxillary sutures are distinct. There is a deep emargination of the border of the jaw 

 at the latter suture, and the maxillary alveolar border is gently convex downwards. 

 The nostril is large and is directed forwards as well as outwards. The premaxillary 

 spines are narrow. The form of the muzzle and jaws when in normal relation was 

 vertical and compressed in front. The premaxillary border of the jaw is rounded and 

 contracted behind the nostril ; the outline then expands backwards. There are but 

 two incisor lieeth, of which the anterior is much larger than the second. Its root is 

 irregular in section, owing to the presence of one or more shallow longitudinal 

 grooves. The pulp cavity of some of the larger teeth is much contracted opposite 

 these grooves by the corresponding internal face, which is disproportionately convex. 

 The anterior two teeth of the maxillary bone are larger than those that follow, the 

 anterior exceeding even the first incisor. The other maxillaries are smaller and sub- 

 equal, excepting the last two, which are the smallest. The crowns of the teeth are 

 lenticular in transverse section, the external side being much more convex than the 

 internal. The cutting edges are defined from the convexity of the latter by a shallow 

 groove at the base of each. The edge is not crenate as in Lcclaps and allied genera, 

 but presents much the same appearance owing to the presence of a transverse corru- 

 gation. There are 14 teeth and empty alveoli in the maxillary bone. 



J\[eas2t}'ements. 



m- m. 



Length of premaxillary axially, to middle of Length of diastema (chord) 0.032 



maxillary suture 0.040 Depth of maxillary at third tooth no 



Length of maxillary bone on alveolar edge from maxillary at antepenultimate tooth... .066 



middle of premaxillary suture 230 Diameter of baseof crown of first incisor tooth.. .015 



Greatest width of the premaxillary 036 first maxillary tooth 018 



Depth of face of premaxillary bone at nostril... .030 fourth maxillary tooth 009 



"The portion of cranium above mentioned displays a number of peculiarities. 

 The orbit is lateral, and has a prominent and convex superciliary border. The zygo- 

 matic arch is so curved upward as to complete the orbit behind by the intervention 

 of a postorbital or postfrontal bone, which separates the malar and squamosal bones 

 from mutual contact. In front of this bone a portion of the frontal forms the super- 

 ciliary border, and in front of this, the prefrontal sends a wide process behind the 

 lachrymal to the orbit. This bone resembles a nasal bone in form, and extends 

 forward, and is decurved at the extremity. The width of the descending or malar 

 process of the postfrontal is such as to partially separate the orbit from the zygomatic 

 fossa. The superciliary surface is swollen, and is interrupted by a transverse groove 

 on the orbital part of the prefrontal. There is a vertical open groove on the malar 

 process of the postfrontal. 



"Several large pelvic bones, coiresponding with those which I have called ischia 

 in Clepsydrops tiatalis, are of a size appropriate to the present species. They include 

 both the ilia, ischia, and pubes in one mass, forming a compressed boat-shaped body 

 with a prominent inferior keel. 



