AXATOMY OF THE SHOE-BILL. 679 



Tendon inserted to phalanx 2 of digit II, In LeptojAilus I have 

 noted it as reaching only the first phalanx. 



Abductor indicls. — Strong muscle arising fleshy from the whole 

 of the radial side of metacarpal II. Inserted to the base of the 

 phalanx 1 of digit II. As in Lej)toptilus. 



Flexor digiti III. — Arises fleshy from the ulnar side of meta- 

 carpal III and is inserted to the base of the first phalanx of the 

 corresponding digit. As in Leptojytilus. 



Adductor jJoUicis.- — -A strong muscle from the metacarpal to 

 the tip of the pollex. 



Extensor poUicis. — This muscle, which is usually described as 

 single, is represented by two distinct and well-developed muscles, 

 a condition which has been described in the case of Struthio^ but 

 not in other birds. Most probably, if it were carefully looked 

 for, it would be found elsewhere. The first of the two is a strong 

 slip from metacarpal I and the tendon of the extensor metacarpi 

 radialis to the radial side of the thumb. It is this muscle that 

 gives ofi^ a slip to the flexor digitorum profundus. The second 

 muscle is from the head of metacarpal II to the base of the 

 thumb. 



Muscles of the Thigh and Leg. 



Ilio-tihkdis internus (Sartor i us). — A large and strong strap 

 arising from the anterior and loAver border of the ilium and from 

 the fascia} over the gluteus medius, and closely imited along its 

 distal border with the gluteus maximus. Normal insertion to 

 the tibia. I find no notable difierence as compared with Storks 

 and Herons. 



Ilio-tibialis (Gluteus maximus). — The origin is entirely ten- 

 dinous and a median tendinous area separates the fleshy anterior 

 and posterior borders. Posteriorly the origin extends backwards 

 half-way over the origin of the biceps, that is to say what Garrod 

 called the post-acetabular part of the muscle, the ilio-tibialis pos- 

 terior, is present. Garrod tried to use the presence or absence of 

 this in his systematic arrangements, but without much success. 

 It is absent in the Steganopods generally, usually absent in Storks 

 but present in Ciconia, absent or very slightly developed in 

 Herons. So far as I can judge, the presence of the post-acetabular 

 portion of this muscle is a primitive condition, and it has been 

 lost or reduced independently in many groups of birds. 



nio-trochanterici. — The externus (text-fig. 129, Gl.a) and the 

 posterior (text-fig. 129, Gl. 2) are both present in the normal 

 condition. The minimus and quartus are represented by a single 

 tendon of origin and muscular belly (text-fig. 129, Gl. 3). In 

 Le'ptoptilus I found these quite distinct in their origin aiid inser- 

 tion ; in Nycticorax they had a common tendon to the femur but 

 separate insertions to the ilium. These muscles, however, vary so 

 much from bird to bird that I cannot attach any significance to 

 their distinctness or fusion. 



