WING BONES. 31 



associated with the hand phalanges in the specimen described." In an article entitled : 

 " The Fingers of Pterodactyls " (Geol. Mag., February, 1904), Professor Williston gives 

 the number of phalanges of the three clawed digits in the hand of Pteranodon, as two, 

 three, four, respectively, but he does not discuss further the occurrence of the very 

 short phalanx which he had previously noted. 



No complete manus of Pteranodon with the parts in their natural position is found in 

 the Marsh Collection, yet the specimens preserved afford conclusive evidence as to the 

 number and arrangement of the phalanges. Figure 2, Plate XXIII, has been prepared 

 to show to better advantage the phalanges of the right manus of Pteranodon sp., No. 1181. 

 Although the bones are disarticulated, it is clear that there are here preserved five 

 phalanges of moderate length, one very short phalanx, and three terminal claws. One 

 of the longer phalanges has a deep process at the proximal end on the lower side. 

 Judging from other material, this process appears to be characteristic of the first phalanx 

 of the fourth digit. 



In another specimen of Pteranodon sp., No. 2428, the greater part of the right manus 

 is preserved ; in fact, the claw-shaped distal phalanges only are wanting. In this manus, 

 as well as in that of No. 1181, there is one very short intermediate phalanx whose length 

 is but a trifle greater that its diameter. Plate XVI, figure 2, based upon No. 2428, pre- 

 sents the writer's mature views of the phalanges of the manus, which, it will be seen, 

 are in accordance with the recognized general formula for the digits of the reptilian 

 hand. The forms of the bones actually preserved are shaded, while the missing claws 

 and the distal end of metacarpal II are represented in outline. The short phalanx already 

 mentioned has been identified as the second phalanx of the fourth digit, thus agreeing 

 perfectly with the condition generally prevailing in the older pterodactyls, where the 

 second phalanx is considerably shorter than its proximal and distal neighbors. Professor 

 Williston's doubt as to whether the short phalanges which he found associated with the 

 manus might not have been interpolated from the foot is removed by comparing the 

 diameter of the phalanges of the manus with those of the podials. The digits of the 

 foot are so much more slender than those of the hand that they may be readily distin- 

 guished by their size alone. Three nearly complete digits of the right manus of Pteran- 

 odon sp , No. 2493, are shown in Plate XXII, figure 3. The arrangement of the phal- 

 anges is evidently unnatural, although these parts are said to occupy the same order as 

 when discovered by the collector. The short phalanx of digit IV, which lies near the 

 distal end of the metacarpal, has clearly been dislodged from its true position, and one 

 of the long phalanges of digit III is wanting. The same forces that moved backward 

 the short phalanx of digit IV may have removed one of the phalanges of the adjacent 

 digit, and closed the gap so formed. 



Reverting again to the large metacarpal V (that of the wing finger), six figures are 

 especially introduced to show its distal articulation with the first phalanx. The adjacent 

 ends of these two bones belonging to the left wing of a large example of Pteranodon 

 sp., No. 2628, are shown in Plate XXIV, figures 1 and 2, taken from the ulnar and 

 radial sides, respectively. Figures 3 and 4 portray the corresponding portions of the left 

 wing of a smaller example of P. occidentalis (Marsh's own identification), No. 1165, at 

 the angle of extreme flexure, though there is some reason to suppose that slight dis- 

 location has here been effected. 



The articulation of metacarpal V with the first phalanx of digit V has been figured, 

 in the examples cited, from bones crushed transversely. To demonstrate better the form 

 MEMOIRS CONN. ACAD., Vol. II. 5 



