No. 472] ANATOMY OF CRYPTOBRANCHUS 307 



length, and articulates with the glenoid cavity of the coracoid by 

 the round, cartilaginous head {H',). Its more or less cylindrical 

 shaft is marked by a large tuberosity {T.) near its proximal end, 

 and is separated from the head by a well marked neck. At its 

 distal end it is broad, somewhat as in the human humerus, and 

 articulates with both the radius and the ulna. 



The radius and the ulna are entirely distinct from each other, 

 and take nearly equal parts in the formation of both elbow and 

 wrist joints, though the ulna, as is usual, is the more closely as- 

 sociated with the humerus. The ulna (Fig. IQ, U.) is slightly 

 longer than the radius (i?.), and strongly resembles the corre- 

 sponding bone in the human arm, though it is, of course, not so 

 long in proportion to its diameter, and its shaft is not so nearly 

 cylindrical in section. Its proximal end is enlarged to form the 

 concave articular surface, the sigmoid cavity, and its distal end 

 is also slightly enlarged, and is provided with a disc of cartilage of 

 considerable thickness. The radius presents no peculiarities in 

 structure. It enlarges rather rapidly from the center towards 

 each end, where well marked discs of cartilage are found. 



The carpus, though composed entirely of cartilage, shows with 

 considerable distinctness the seven elements of which it is made 

 up. Two elements articulate with each of the forearm bones: 

 on the radial side are the radiale (/?'.) and the centrale (Cn.), the 

 latter lying in about the center of the carpus; on the ulnar side are 

 the ulnare {V .) and the interraetliutn (7.) Uniting the four 

 elements above descril)ed with the metacarpals are three distal 

 carpals (Fig. 10, 3, o), one of which is united with two of the 

 metacarpals. On the anterior appendage are four digits, each 

 of which is made up of an elongated tnetacarpal clenuMit .1/.) 

 and two short phalangeal elements {P.), of wlildi the mure 

 distal tapers to an almost claw-like sharpness. The tun miiidle 

 digits which are of about the same length, are somewhat h.nuer 

 than the two outer ones. There is no sign, on the fourth digit, 

 of the third phalangeal element described by Osawa in the Japanese 

 salamander. The relative sizes of the metacarpal and phalangeal 

 elements are ahout the same in each of the four digits. 



