m 



vated ridge. Anteriorly, it presents an elevated crest for muscular insertion. 

 This terminates abruptly, and is followed distally by a deep notch. Distal to 

 this is another prominence of the bone, also probably an insertion. Antero- 

 posterior diameter (flattened), 24 lines. 



The lateral carpal is short and wide ; both its articulations are simple 

 and concave. Both outlines are keeled; one very strongly at one end, and at 

 the other presenting beyond the articular surface for the distal carpal, a wide 

 prolonged process for muscular insertion. Length of carpal without proc- 

 ess, 13 lines; process, 4 lines; diameter, widest extremity, 11 lines. This 

 indicates a very stout carpus. The phalange is penultimate, and is remark- 

 able tor its small size, perhaps indicating an external rudimental digit. It 

 is only supposed to belong to the anterior Hmb from its having been found 

 with the preceding bones. It is slender, and has a convex distal articulation, 

 divided by a trochlear groove, and the concave proximal one in like mannei 

 divided by a trochlear carina. Length, 9 lines ; proximal depth, 3 lines. 



'1 his species is the largest Pterodactyle as yet known from our continent; 

 the end of the wing-metacarpal exceeding in diameter that of the species 

 described by Professor Marsh from the same region by more than four milli- 

 meters. 



From near Butte Creek, Kansas, from the yellow chalk. 



Pterodactylus occidentalis. Marsh. 



Established on wing-metacarpals and phalanges of three individuals. 

 The articular extremities indicate a species from one-half to two-thirds the 

 size of the last-named. Those of the metacarpal are very prominent above 

 as well as below, and there is no distinct ridge in the trochlear groove 

 between them. The inner condyle does not stand on a base with an acute 

 posterior ridge, but overhangs a rather obtusely-edged support. There is no 

 second ridge on the outer (trochlear) side of it. The same condyle termi- 

 nates abruptly posteriorly on the superior face of the shaft. Width of con- 

 dyle in No. 1, 11 lines; in No. 2, 13 lines; vertical diameter, inner condyle. 

 No. 1, 11 lines; transverse diameter of the shaft above, 8 lines. 



The proximal articular surfaces of the proximal wing-phalanges are 

 deeply concave: the inner protected by an elevated margin behind; that of 

 the outer much lower. They are separated chiefly by a deep emargination 

 l)ut on their short adjacent portions by a low ridge. The process for liga- 



