648 



PROF. H. G. SEELEY ON 



[Aug. 1900, 



plate appears to be about 2^ inches ; it is slightly concave from side 

 to side. The foramen magnum is vertically oblong, and fairly large. 

 On its right side appears to be the right occipital condyle, much less 

 elevated than in Gomplior/nathus or Cynognathus, but better marked 

 than in Lyeosaurus or Tropidostoma. Above this region the upper 

 narrow part of the occipital plate leans a little forward, and is 

 slightly concave, as in most Theriodonts. 



The squamosal bone is exposed on its inner aspect, very 

 slightly displaced on the left side, so as to be depressed and in- 

 clined a little outward in its hinder part, and seen from the inner 



lateral aspect appears 



Bestoration of SMI of Dioranozygoma ™ der * au £* sll0uld be ' 



leptoscelus, gen. et sp.nov. (I nat.ske). The . ™ hou ? t ma y be 



carried upon its outer 



side in the usual way, 

 since it is seen, on the 

 inner side of the zygoma, 

 anteriorly, to form the 

 lateral part of the arch 

 in front of the squamosal 

 bone. This suture is 

 much farther forward 

 than in the known genera 

 of Cynodontia or Gom- 

 phod.on.tia, and appears 

 to indicate that the 

 malar bone was rela- 

 tively smaller than in 

 the better-known Therio- 

 donts. The squamosal 

 has not quite the rela- 

 tions found in Dicyno- 

 donts. It is the most 

 remarkable bone of the 

 skull which is evidenced, 

 in being a thin com- 

 pressed plate prolonged 

 backward behind the 

 occipital crest so as to 

 add nearly one-third to 

 the length of the skull : 

 it is entirely unparalleled. The quadrate articulation is not seen, 

 but on the right side is a fragment of a squamous bone descending 

 below and behind the quadrate region, which may be a further 

 expansion of the quadrate bone. Its inferior edge is rounded ; the 

 posterior border is broken. The visible surface of that part of 

 the squamosal which forms the outer hinder boundary of the 

 zygomatic arch has a convex external contour, which becomes 

 rounded behind, and is then reflected upward on the inner or 

 occipital edge. The bone terminates in front below the level of the 



[The shaded portions are those not preserved 

 in the actual specimen.] 



