1004 MESSRS. B. C. A.. WINKLE A>^D F, G. PARSONS ON [DeC. 19,- 



Gastrocnemius. — This muscle, amongst the Edentata, has, with 

 certain exceptions, the typical mammaUan arrangement. In the 

 Bradypodidce rhe two heads do not unite until they reach the cal- 

 caneum, but they are nob twisted in such a way that the inner 

 becomes superficial and then external (c/. Journal of Anat. & Phys. 

 vol. xxviii. p. 414). This is true of Bradijpus (1, 2) and Cholcepus 

 (8, 9, 10). In the Manidce. (29, 32, 33) the external head is very 

 large and rises a long way up the shaft of the femur — a condition 

 far exceeding anything which we have hitherto observed in any 

 other mammal. It is interesting to notice that nearly all observers 

 have recorded the absence of fabellse except in the Orycteropodidce. 

 Soleus. — Among the Bradypodidce the soleus often I'ises quite 

 low down on the fibida in Bradypus, in which animal it arose in 

 one case (5) from the middle, and in another (1) from the lower 

 third of the bone. It is inserted into the calcaneum without 

 joining the tendo Aehillis (1, 2). In Gholoepus the chief insertion 

 is also into the calcaneum in front of the tendo Aehillis, but 

 Humphry noticed that some of its fibres were continuous with 

 those of the accessoriiis. Among the MyrmecopJiagidce its origin 

 was chiefly from the fascia over the deep flexor muscles in 

 Myrmecophaga (11) \ In the last-mentioned animal, in Taviandua 

 (14), and in Cyclothiirus (19, 20) it is inserted as in the Bradypodidce. 

 In the Dasypodidce it seems usually to join the outer head of the 

 gastrocnemius, but our information is not very clear upon this point. 

 In the Manidce. (29, 32) and Orycteropodidce (35, 36) its insertion 

 is as in the Bradyjjodidce and Myrmecopliagidce. It will thus be 

 seen that the Edentata as an order are characterized by the 

 separate insertion of the soleus and the absence or incompleteness 

 of the tendo Aehillis. 



Plantaris. — This muscle is liable to a good deal of variation in 

 the Edentata, and is likely to be confused, on the one hand, with 

 the femoral head of the flexor cruris lateralis (biceps), and, on the 

 other, with the flexor tibialis and tibularis. In the Bradypodidce 

 the muscle was absent in one specimen (1), but in three others (2, 

 4, 5) it was present as a very large muscle which rose from above 

 . the external condyle of the femur, and was inserted into the long 

 flexor tendons in the sole of the foot. It is described by some 

 writers as an extra head of the long flexors of the toes. In 

 Clioloepus (8, 9, 10) the muscle is absent, but the condition in this 

 form will be again referred to under the head of the tibialis posticus. 

 Among the MyrmecopjJiagidce it is present in Myrmecophaga (11) and 

 has the usual mammalian insertion into the plantar fascia. In 

 Cyclotlmrus (17, 19, 20) it is also present, and is inserted into the 

 elongated ossicle on the tibial side of the foot. This insertion is 

 interesting when compared with that which is found in the hand 

 of PecUtes (cf. Proc. Zool. Soc. 1898, p. 867), in which the palmaris 

 longus, the serial homologue of the plantaris, is inserted into the 



' In (12) it bad the generalized nmmmaliau origin- from the back of the head 

 of the fibula. 



