o/Bradypus tridactylus. 61 



ligament ; and into it the palmaris-longus tendon is inserted. 

 On slitting np this structure, the flexor digitorura is exposed. 

 This muscle is single, and jilajs the part of flexor sublimis, 

 flexor profundus, and poUicis. It arises from the inner condyle 

 of the humerus, from the front of the radius, ulna, and inter- 

 osseous membrane; all its fibres unite to form one mass, which 

 ends in three very strong tendons passing to the last phalanges 

 of the three digits. Eacli tendon is bound down by an enor- 

 mously strong sheath, and when examined seemed to be com- 

 posed of two laterally united halves, as a groove extended in the 

 centre of tlieir distal ends for nearly one-fourth of their thick- 

 ness. The Ai resembles the Orycterope in having no sesa- 

 moid bone in the palm, but differs from it in being devoid of 

 all traces of lumbricales. Each tendon has several synovial 

 vincula or retinacula binding it in its place. No sesamoid 

 bone exists in the Tamandua, the Two-toed, or the Great Ant- 

 eater ; but in the Armadilloes they exist in D. sexcinctus, tr{~ 

 cinctusj gigcis^ Cldamypliorus truncatus^ as also in Echidna 

 hystrtx and Oniithorhi/nclius. 



We could find no true supinator longus in the Armadillo ; but 

 it is well developed in the Tamandua and the Orycterope, and 

 in the Ai proportionally best of all, and split into two strata, 

 as was the case with the pronator teres ; the longest of these was 

 inserted into the lower extremity of the radius, and by a few 

 fibres into the external lateral ligament of the wrist. In the 

 Two-toed Anteater it is similarly divided ] but it does not seem 

 to be present in the M.Juhata'j at least Pouchet does not men- 

 tion its existence. 



The supinator brevis was small and characteristic, pierced 

 by the posterior interosseous nerve. Its origin was purely 

 humeral, and its insertion, as usual, was radial. Its position 

 is similar in the Armadillo ; and its nervous relation appears 

 constant in these animals. It seems to be larger in the Oryc- 

 terope, as it extends in that creature for one-half of the radius. 

 It exists likewise in the Great, the Two-toed, and the Tamandua 

 Anteaters. 



The extensor carpi radialis is a single nniscle with a double 

 tendon inserted into the first and second metacarpal bones. It 

 has two tendons, according to ]\Ir. Galton, in the Orycterope — 

 one, according to Prof. Humphry. In this animal the former 

 author observes that the tendon representing the extensor carpi 

 radialis brevior seemed to be the more direct continuation of 

 the original muscle ; but in Bradt/jms there is no difference 

 between the parts of the muscle furnishing the broad flat 

 tendon. In Cholwpxs it is circumstanced similarly, and in 

 the Anteaters and ArmadiUi:>es it is the same. 



