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Show 1894.] MAMMALIAN H A N D AND FOOT. 363 ulna to the aponeurotic sheaths of these digits, like the ext. in Man. 3. DIPUS JACULUS. From the Pp., which is of enormous size, a strong muscle- m. transversus carpi-arises ; it is inserted into the fifth metacarpal bone. A very large superficial muscle is situated on the flexor side of the forearm and hand : it takes origin from the humerus and the ulna and ends by tendons on the Pp. and on the top of the pisiform (Pm.). As there is another superficial muscle with distinct tendons running down to the hand, and there are also flexores digitorum sublimis and profundus, I suppose that those two superficial muscles are parts of the palmaris longus (the flexor digitorum superflcialis). I could not make further investigations, this animal not being well preserved. d. UNGULATA. 1. HTRAX BRUCEI. a. Flexores. From the tendons of the palmaris longus arises a flexor brevis superflcialis; this is common in the foot, but very seldom met with in the hand. As this animal has not four digits (Mivart) but five (Dobson), there are muscular bellies to each digit except the third, i. e. four. (Dobson describes only three.) The belly for the thumb is 3'5 mm. long and 2-5 mm. broad. The tendons of this superficial flexor are cleft and let pass the deep tendons. The three inner bellies of the flexor brevis are supplied by the medianus, the outer one (5th digit) by the ulnaris. Ulnaris internus consists of two muscles (taking origin from the humerus and the ulna). B. Extensores. The radialis externus, situated under the ext. poll, longus, ends by four tendons :-the first is inserted into the second metacarpal bone; the second and third into the third metacarpal; the fourth into the unciform. The ext. pollicis is very strong, its broad tendon ends on the small rudimentary thumb (quite as in the Pp. in animals with " five " digits). The ulnaris externus is also very strong, it is inserted into the fifth metacarpal bone. The extensor digitorum communis is perforated by the (2) tendons of the extensor minimi (el quarti) digiti. 2. ELEPHAS AFRICANUS (Embryo). (Roy. Coll. Surg.) The specimen was already dissected for the Collection. |