MUSCLES OF THE HIND LIMB. 25 



portion becomes trifid distally, and eaeh division sentls a tendon to the secontl, 

 third, and forth digits respectively. This tendon bridges the groove of the 

 profundus. 



The fiexor profundus digitorum (Plate 6, fig. G, (/) arises as in Gymnura and 

 Centetes from five heads, and thus differs from that of Potamogale in wliicli hut 

 three are described. The first of these heads is superficial, from the anterior 

 edge of the epitrochlea; its large tendon inserts into the common tendon on the 

 radial side at the wrist. This division is more or less distinct throughout its 

 distal union with the main mass of the tendon and has been homologizetl l:)y 

 Dobson with the jlexor longus pallicis. Two smaller muscles, foi'ming tlie 

 second and third heads, arise in close association from the anterior surface of the 

 epitrochlea and the anterior edge of the great sigmoid notch. Their tendons 

 become confluent and join the main palmar tendon medially proximal to the 

 insertion of the first division. The heaxl of flexor sublimis separates the head of 

 the first division from the common origin of the second and third. The fcjui'th 

 head arises as a large fleshy muscle along the ectal side of the ulna from the 

 olecranon to within about 15 mm. of the distal end of the ulna where its flbers 

 merge with those from the fifth division whose origin is from the proximal two 

 thirds of the ental border of the radius. These five divisions unite to form a 

 thick flat tendon at the wrist. This divides at the base of the metacarpals to 

 form the usual five branches, one to the lower surface of each digit. This muscle 

 in Solenodon seems most nearly to resemble that of (iymnura in possessing five 

 distinct heads. In Centetes the condition is essentially similar, but the closely 

 associated second and tlfirtl heads are united into a single division. In Potamo- 

 gale the number of heads seems to be still further reduced. 



MUSCLES OF THE HIND LIMB. 



The psoas Jiutgnus (Plate 4, fig. 2, o) apiieai's to be essentially similar in its 

 relations to that of Gynmura, Erinaceus, and Centetes. It arises from the 

 transverse processes of the lumbar vertebrae as a thick muscular mass and 

 becomes confluent with the iliacus from the ventral side of the anterior ramus of 

 the ilium. It then tapers to its insertion on the lesser trochanter of the femur. 



The psoas parrus (Plate 4, fig. 2, p) arises as a flat ellipsoidal muscle from the 

 ventrolateral portion of the first lumbar and the anterior portion of the second 

 lumbar vertebrae. It then passes posteriorly as a thin flat tendon from 2 to 

 3 mm. wide and 30 mm. long to insert on the anterior edge of the pelvis, just 



