rPOX HTPESODAPEDOX GOEDOXI. 



691 



as Xo. 1, much of the skeleton of the right fore limb is preserved. 

 The right humerus is 40 millim. long, and has widely expanded 

 proximal and distal ends. The radius has about the same length. 

 There are more or less well-preserved remains of five metacarpals. 

 The first has about half the length of the second, which is about 

 equal to the third. 



In the specimen (No. 2) all five digits of the manus are dis- 

 played. The fifth metacarpal, which is broad and short, as in Splie- 

 nodon, and three or four of the phalanges of the fifth digit are in place 

 (Plate XXYII. fig. 3). In all respects, this foot is more like that of 

 Splienodon than that of Hyperodctpedon. 



The impressions of the ischia are very well shown in No. 3 (Plate 

 XXYII. fig. 4, is). They are broadly triangular in shape, with the 

 angles rounded off. The symphysial side is 25 millim. long ; while, 

 from the symphysis to the acetabulum, transversely, the bone measures 

 20 millim. In front of the left ischium there is seen, in the place 

 which ought to be occupied by the pubis, the impression of a broad 

 flat plate (Plate XXYII. fig. i,pb) t 25 millim. from side to side by 

 10 antero-posteriorly, the posterior edge of which is, for its inner 

 two thirds, in close contact with the front edge of the ischium, 

 leaving only a small space to represent the obturator foramen. I 

 cannot take this impression to represent anything but the pubis, 

 though its form and position are somewhat unusual. The femur is 

 57 millim. long, and the shaft is curved like an \. The tibia and 



fibula are each 50 millim. long. The astragalus and calcaneum are 

 separate (as in Splienodon), and have the ordinary Lacertilian form. 

 A large distal tarsal bone (as in Splienodon) affords an articular 

 surface for the fifth metatarsal, which, with the four phalanges of its 

 digit, is preserved (Plate XXYII. fig. 4 3 v). This digit differs but 

 little in size and form from the corresponding digit in Splienodon : 

 and it is therefore remarkable that the fourth metatarsal of Rlrynclio- 

 saurus is very much broader than that of Splienodon, and half as 

 long again. The third and second metatarsals are nearly as broad, 

 but shorter. The first is relatively shorter and thicker (Plate XXYII. 

 fig. 5). 



Two imperfect series of tail-vertebrEe show that, in the anterior 

 caudal region, the vertebra? were provided with long and strong 

 chevron bones (Plate XXYII. fig. 2). 



The evidence which has now been adduced appears to me to prove 

 that Hyperodapedon, Rliyncliosaurus, and Splienodon constitute a 

 peculiar group of Lacertilia, the skeletons of which are distinguished 

 from those of all other recent or extinct known forms by the com- 

 bination of the following characters, namely : — the premaxillary 

 rostra ; the longitudinal series of palatal teeth, bounding a groove, 

 between which and the maxillary teeth the hinder mandibular teeth 

 are received : the abdominal ossicles ; and the absence of proccelous 

 praesacral vertebrae. This group of Splienodontina falls into two 

 families, the Eliynchosaiirid.ee and the Sphenodontidce. 



The ffliyncliosauridce have a single external nasal aperture 



