18 FOSSIL REPTILIA OF THE 



on the opposite surface (fig. 7) ; but both these surfaces are irregularly undulated, 

 as shown in the figures ; the more concave surface being also impressed by a deep 

 hemispheric pit. I conjecture that this bone formed the proximal part of the 

 carpus, and that the pit may have received a process of the distal end of one of 

 the antibrachial bones. The opposite, probably distal, and more convex surface 

 (fig. 8) is divided into two slight convexities, by a shallow, wide channel, crossing 

 the bone obliquely. The convexity («) meets the concave surface on the other side 

 of the bone («>/) by their convergence to the basal border or margin, which presents 

 a slight notch. The opposite end of the bone forms the obtuse apex (d), which 

 is a little bent down towards the concave side. On this side (fig. 7) the notch is 

 continued into an angular channel, which divides the two shallow, concave sur- 

 faces ( e and /) occupying the basal half of this surface ; a little nearer the apex 

 than the middle of the bone comes the hemispheric pit, with a small depression 

 on one side of it. 



Fig. 9 shows the thickest or deepest, non-articular side of the bone, sloping to 

 the end of the facet (/), and with the apical tuberosity (d) at the opposite end. 



Fig. 10 is taken looking upon the convex surface from the notched 

 base (a). 



Fig. 8 may correspond with the surface of the carpal bone in Pteroclactylus 

 suevicus, marked 1, in the bones of the left wing in Professor Quenstedt's Plate ; 

 and the side view of the same bone in the carpus of the right wing gives an 

 indication of the produced apex. The outline of the large proximal carpal in 

 Pteroclactylus (Ramphorhynchus) Gemmingi, in M. v. Meyer's Plate, accords 

 in a general way with the profile of the narrower side of the present bone, 

 which, for the convenience of indication and description, might be called the 

 "scapho-cuneiform." I have no proof, however, from knowledge of its precise 

 connexions, of the accuracy of this determination ; but strongly suspect that the 

 bone may represent more than one of the proximal carpals in the mammalian 

 wrist, and probably the two proximal bones in the carpus of the crocodile. 



In Tab. II, fig. 6, a scapho-cuneiform bone is figured, which, from its size, 

 might belong to Pteroclactylus simus ; it differs from that in Tab. IV, fig. 7, 

 not merely in size, but, apparently, in a greater relative breadth of the surfaces 

 (e and /) ; their margins forming the base of the triangle have been, however, 

 abraded. 



The second large wrist-bone (Tab. IV, figs. 5 and 6), if the foregoing be rightly 

 compared, will match with the carpal bone articulating with the proximal end of 

 the metacarpal of the fifth or wing-finger in the plates of Pteroclactylus suevicus, 

 and of Ramphorhynchus Gemmingi, above cited ; and it will consequently 

 answer to or include the " unciforme," by which name it will be here described 

 and figured. 



