MUSCLES OF THE FORE LIMB. 23 
it with the proximal end of the radius at the point where radius and ulna meet 
at the articulation with the humerus. This is the condition likewise in Centetes, 
and practically that found in Gymnura, where, however, only the ulnar insertion 
is described. In Dobson’s specimen of Solenodon cubanus he found two heads 
to this muscle. The second he describes as ‘‘a long and very slender tendon 
from the coracoid process immediately above that of the coraco-brachialis.”’ 
This, he states, ‘“‘becomes muscular low down, and unites with the belly of the 
glenoid head about the commencement of the lower third of the humerus; the 
muscle thus formed terminates in a tendon which is mainly inserted into the 
radius.”’ Possibly the double origin of the biceps in his specimen was an indi- 
vidual anomaly, or the condition in the Cuban species is different from that 
obtaining in S. paradozus. 
The brachialis does not differ essentially from that of Gymnura and Centetes. 
It arises from the posterior side of the humerus between the two tuberosities 
and along the ectal margin of the crista deltoidea to insert into the capsular 
ligament and the inner dorsal edge of the radius. 
The extensores (carpi) radialis longior et brevior (Plate 6, fig. 5, b) are not 
separate muscles, but form a single rather flat muscle that originates from the 
antero-proximal portion of the epicondylar ridge. At about the beginning of 
the distal third of the radius this muscle becomes a thick tendon that passes 
ental to that of the extensor ossis metacarpi pollicis, and splits into two tendons 
that go to the bases of metacarpals 2 and 3 respectively. 
The extensor digitorum communis (Plate 6, fig. 5, a) arises by tendinous 
fibers from the ectal point of the epicondylus. Near the distal end of the 
radius it passes into a flat tendon that breaks directly into four small branches, 
one each to the dorsal surface of digits 2 to 5. 
Just distal to the origin of the last, arises the extensor minini digiti (Plate 6, 
fig. 5, g) from the ectal edge of the epicondylus and from tendinous fibers from 
the communis and the extensor carpi ulnaris. It passes into a strong tendon 
that divides into two branches at the metacarpals. The ectal branch passes 
to the dorsal side of digit 5 and the ental branch dips under the outermost divi- 
sion of the communis to insert on the ecto-lateral face of the last phalanx of digit 
4. This condition is essentially that in Centetes. 
The extensor carpi ulnaris (Plate 6, fig. 5, e) arises just distal to the origin 
of the preceding, at the outer distal edge of the epicondylus and from fibers 
along the greater sigmoid notch. At about 18 mm. from its insertion it becomes 
a thick round tendon, passing to the ecto-proximal margin of metacarpal 5. 
