MUSCLES OF THE FORE LIMB. 23 



it with tiie pnjximal end of the rachus at the point where radius and uhia meet 

 at the artiouhition witli the Imnierus. Tliis is tlie condition likewise in Centetes, 

 and practically that found in dymnura, 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. paradoxus. 



The brachialis does not differ essentially from that of Gymnura and Centetes. 

 It arises from the posterior side of the humerus I)et ween the two tuberosities 

 and along the ectal margin of the crista deltoidea to insert into the capsular 

 ligament and tlie inner dorsal edge of the radius. 



The extensorcs (cai-pi) radialis longior et brevior (Plate 6, fig. 5, b) are not 

 separate muscles, but form a single rather fiat 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 (jf metacarpals 2 and 3 respectively. 



The extensor digitorum communis (Plate 6, fig. 5, «) 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 cUgits 2 to 5. 



Just distal to the origin of the last, arises the extensor minini digili (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 brancli 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 tdnaris (Plate 6, fig. 5, c) arises just chstal 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. 



