o/" Cyclotliiuais didactylus. 259 



in tlic Ai, according to Meckel (Vergleicli. .Vnat. iii. p. 63o) 

 and Prof. Macalister [loc. cit. p. 66), and in Nycticehns tarcU- 

 (jradus^ according to Mr. Mivart and Dr. Miirie (Proc. Zool. Soc. 

 Feb. 1865, p. 251). It is significant that Prof. Macalister has 

 recorded ( Journ. of Anat. ser. 2. vol. ii. p. 108) the occurrence 

 of a sesamoid in tlie tendon of origin of the supinator brevis 

 in a female liuman subject, "which muscle he considers to be 

 the serial homologue of the popliteus. 



The plantaris arose from the lower surface of the femur, 

 behind the external condyle, in advance of the origin of the 

 femoral head of the biceps. The muscle is continued into a 

 long slender tendon, wliich passes under the gastrocnemius to 

 the inner side of the leg, and, after broadening out, is inserted 

 partly into the calcaneum, partly into the exti-emity of the 

 strigil-shajjed accessory bone of the tarsus. The termination 

 of this muscle is unlike that which is usual in the Edentata 

 (Macalister, loc. cif. p. 6G)j since it is not prolonged into the 

 sole. 



The tibialis posticus arose from the middle of the posterior 

 surface of the tibia, just below the insertion of the popliteus, 

 with wliich it is here blended, also from the posterior part of 

 the head of the fibula. Its tendon passes under a strong liga- 

 mentous pulley at the internal malleolus, and is inserted into 

 the fibular and inferior aspect of the strigil bone, not far from 

 its free extremity. 



A muscle arose from the inner aspect of the head of the 

 fibula, covered by the origin of the tibialis posticus. It soon 

 became tendinous ; and its long tendon passed obliquely to the 

 inner side of the calf, and at the inner malleolus ran under a 

 pulley situated posterior to and slightly below that under 

 which the tendon of the tibialis posticus passes. It was in- 

 serted into the fibular side of tlie strigil bone, close to its base 

 and in advance of tlie insertion of the tibialis posticus. This 

 muscle, if not a dificrcntiatcd slip of the tibialis posticus, which 

 it most probably is, may be the ficxor longus hallucis. Prof. 

 Hyrtl deseribes, under the name of " tibialis posticus accesso- 

 rius," a similar muscle as present in Chlamijthphorits^ " qui 

 tibialem posticum via^ comitcm laborisque socium legit." I 

 found a like muscle in Dasj/pus (Trans. Linn. Sue. xxvi. 

 p. 558) ; and ]\Ir. Wood records (Proc. Poy. Soc. June 18()5) 

 the occasional occurrence of such in the human su))ject. 



The flexor longus digitoruni was a strong bipenniform mus- 

 cle, arising from the up})er three-fourths of the tibia and fibula. 

 It became tendinous on reaching the sole; and the branches of 

 its tendon terminated each at one of the four functional digits 

 of the foot. 



