MUSCLES OF THE HIND LIMB. 31 



to be a peculiarity not hitherto noted, Init was unmitstakaljly present in S. 

 paradoxus and may be anomalous. 



Tlie peroneus brevis antl the peroneus quinti digiti arise on the antero-external 

 aspect of the fibula, the latter from the external aspect for a distance of about 

 11 mm. distal from the head, and the former more internal, f(jr a slightly greater 

 distance. The tendons of both are invested in a common sheath and pass 

 together posterior to the external malleolus and beneath the tendon of peroneus 

 longus. Peroneus quinti digiti is inserted into the distal phalanx of digit 5, 

 while the peroneus brevis passes to the ecto-proximal end of the fifth metatarsal. 

 Both these tendons are simple and show no trace of secondary divisions to digit 4 

 as described for Gymnura and Centetes by Dobson. Solenodon thus resembles 

 Potamogale in the single attachments of these muscles. 



Tin- extensor hallucis longus arises from tlie middle third of the fibula and 

 adjacent interosseus ligament and passes to the distal phalanx of digit 1 on the 

 dorsal side, through the same large groove on the front of the ankle, as tlie 

 extensor longus digitorum and the tibialis anticus. 



The tibialis posticus (Plate 4, fig. 2, ;) is concealed by the flexor longus 

 digitorum. It arises from the proximal end of the fibula on its posterior side 

 and is more or less connected by muscular fibers with the flexor longus hallucis. 

 After crossing to the ental aspect of the limb, it passes as a small tendon through 

 a groove on the distal part of the tibia to the insertion into the ento-lateral 

 process of the os calcis at its anterior end, not into the naviculare or scaphoid as 

 commonly. Dobson states that this muscle in Solenodon cubanus retains its 

 usual insertion into the naviculare, but in »S'. paradoxus it was found on each side, 

 inserted unequivocally as above noted. 



The flexor longus digitorum, or digitorum tibialis (Plate 4, fig. 2, I) arises 

 mainly from the posterior proximal portion of the tibia. The tendon passes 

 through the same groove on the ental aspect of the tibia as that of the tibialis 

 posticus, and ectal to it. It becomes inserted into the ventral surface of the 

 flexor longus hallucis. At the base of the cari)als, it gives off a small branch to 

 the rudimentary fii'st metatarsal. This muscle in Solenodon resembles the 

 corresponding one in Potamogale, rather than that of Centetes whose curious 

 development has been described by Dobson. In Gymnura it is merely united 

 with the next. 



The flexor longus hallucis (or digitorum flbularis) (Plate 4, fig. 2, /) takes 

 origin from nearly all but the distal portion of the i)osterior side of the fibula 

 and adjoining middle third of the tibia. It is much larger than the flexor 



