o/ Cyclothurus didactylus. 255 



The tendon of the deep flexor does not contain any sesamoid 

 bone. 



From the ulnar side of the deep flexor tendon of the third 

 digit, just before it passes under the " perforated " flexor, is 

 given off a comparatively small tendinous slip, which becomes 

 muscular, and has a fleshy attachment to the radial side of the 

 last division of the rudimentary fourth digit. 



From the angle formed by the junction at origin of the 

 deep flexor tendon of the index with the tendon for the third 

 digit rises a vermiform muscle, similar to the one just described, 

 which is attached to the radial side of the proximal phalanx of 

 the third digit. 



These two muscles are probably lumbricales — muscles 

 which, according to Prof. Macalister (Ann. & Mag. Nat. Hist. 

 July 1869, p. 61), are absent in the Ai. 



The interossei are five in number : — 



1. A fairly developed muscle, arising by a tendon from the 

 inferior process of the unciform bone, and passing to the ulnar 

 side of the base of the proximal phalanx of the third digit. 



2. Above this arises, from the ulnar side of the unciform 

 process, another and smaller muscle, which passes to the rudi- 

 ment of the fourth digit. 



3. A fair-sized muscle, terminating at the ulnar side of the 

 proximal phalanx of the index, and arising from the middle 

 of the palm, from adjacent parts of the bones of the two meta- 

 carpals. 



4. A delicate muscle arises from the unciform bone, covered 

 by the muscle described above as passing to the third digit. 

 It runs obliquely across the palm ; and its delicate tendon 

 seems to join the muscle which goes to the index. 



5. To the radial side of the proximal phalanx (metacarpal ?) 

 of the index passes a muscle from the rudimentary pollex 

 (trapezium?). 



The gluteus maximus was represented by a thin muscular 

 sheet inserted by a strong tendon into the middle of the outer 

 edge of the femur, at about the point where the third trochanter 

 would be looked for. According to Meckel (Archiv, p. 48, 

 and Vergleich. Anat. p. 577), the insertion is along the lohole 

 of the outer edge of the femur. The tendon is continuous an- 

 teriorly with the fascia in which the " portion ventrale " (Cuv.) 

 of the panniculus terminates. The muscle arises from the 

 crest of the ilium and from that edge of the bone which is in 

 apposition to the sacral vertebrte, also from an aponeurosis 

 which covers the origin of the caudal muscles. 



The gluteus medius is a thick muscular mass which takes 

 origin from the whole of the external (gluteal) fossa of the 



18* 



