EMERSON: ANATOMY OF TYPHLOMOLGE. 
57 
length compared with the distance from the tip of the procoracoid 
to the anterior border of the glenoid fossa is in the ratio of 10 : 5, 
while in Proteus the ratio is 8 :5, and in Necturus 5:5. 
The humerus, like all the long bones of the limbs, consists of a 
bony diaphysis and two cartilaginous epiphyses, the proximal one, 
or head, being rounded and articulating with the glenoid fossa. The 
diaphysis is battened both proximally and distally, but in different 
directions, which gives it a twisted appearance. The proximal third 
is battened laterally bearing on its outer surface a ventro-lateral 
ridge, the crista deltoidea, the insertion of most of the shoulder 
muscles. The middle third of the diaphysis is more cylindrical in 
shape, but the distal third is battened dorso-ventrally, as is the dis¬ 
tal epiphysis. The outer portion of this epiphysis is rounded and 
articulates with a shallow socket on the head of the radius, while the 
inner portion articulates less hrmly with the head of the ulna. 
The ulna and radius are long and thin, their length bearing about 
the same ratio to that of the humerus as in the Proteidae. The 
proximal epiphysis of the ulna is slightly prolonged to form the 
olecranon and is, therefore, somewhat longer than the correspond¬ 
ing epiphysis of the radius. Both bones are battened dorso-ventrally 
at their proximal ends. Their distal epiphyses are oblong in shape, 
that of the radius articulating with the carpal elements, radiale and 
intermedium, that of the ulna with intermedium and ulnare. 
The carpus consists of eight small cartilaginous pieces arranged in 
two rows, three in the proximal and four in the distal one, with the 
eighth piece, centrale, between. The proximal row contains the 
largest pieces, the outer being the ulnare, the median the interme¬ 
dium, and the inner the radiale. The distal row contains carpale 
2, 3, 4, and 5, all articulating with centrale, which also articulates 
with intermedium and radiale. Carpale 1, together with the hrst 
digit, is missing. The second, third, fourth, and hfth digits are pres¬ 
ent, each consisting of a metacarpal, articulating proximally with the 
corresponding carpale, and one or more phalanges. 
There are eight phalanges: one in the second digit, two in the 
third, three in the fourth, and two in the fifth. The distal ones are 
very short, each having a cartilaginous proximal epiphysis and a dis¬ 
tal bony portion which tapers to a blunt point; the other phalanges 
and the metacarpals are slightly longer, each having a bony shaft 
and two cartilaginous epiphyses. 
