THE MYOLOGY OF THE DOG. 355 



and closely applied to, but not anchylosed with, the tibia. 

 The hallux is usually rudimentary ; only the metatarsal, and 

 the basal phalanx, being represented by two small ossicles. 

 In some breeds of dogs, however, the hallux is fully developed. 



In the myology of the Dog the insertion of the tendon of 

 the external oblique muscle of the abdomen presents some in- 

 teresting peculiarities. The outer and posterior fibres of this 

 muscle end in a fascia which is partly continued over the 

 thigh as fascia lata^ and partly forms an arch (Poupart's liga- 

 ment) over the femoral vessels ; by its inner end it is inserted 

 into the outer side of a trian2:ular fibro-cartilao-e, the broad 

 base of which is attached to the anterior margin of the pubis, 

 between its spine and the symphysis, w^hile its apex lies in 

 the abdominal parietes. The internal tendon of the external 

 oblique unites with the tendon of the internal oblique to form 

 the inner pillar of the abdominal ring, and is inserted into the 

 inner side of the triangular fibro-cartilage. The pectlneus is 

 attached to the ventral face of the cartilage ; the outer part 

 of the tendon of the rectus into its dorsal face ; but the chief 

 part of that tendon is inserted into the pubis behind it. This 

 fibro-cartilage appears to represent the marsupial bone, or 

 cartilage, of the Monotremes and Marsupials. 



The trapezius and the sternomastoid coalesce into a single 

 muscle ; and, in the absence of a complete clavicle, the outer 

 fibres of the latter and those of the anterior part of the del- 

 toid are continuous. In this way a muscle which has been 

 called levator humeri proprius is formed. The omoJiyoid smd 

 the subdavius are absent. There is a trachelo-acromialis and 

 a dorso-ep>itrochlearis. The supinator lojigus is absent, but 

 there is a pronator quadratus. The extensor comjjiunis digi- 

 torum manus divides into four tendons, in which sesamoid 

 bones are developed over the articulations between the first 

 and second phalanges. The extensor 2^ri7ni internodii pollicis 

 is absent. The extensor secundi internodii is one muscle with 

 the extensor indicis. Tlie extensor minimi digiti sends ten- 

 dons to the third, fourth, and fifth digits. All these deep ex- 

 tensors have sesamoid bones over the metacarpo-phalangeal 

 articulations. The palmaris longus appears to be absent; 

 but all the other flexors of the manus, even the palmaris hre- 

 vis, are represented. The tendons of the flexor 2^ oil ids longus 

 8,ud flexor digitorum perforans are united. The divisions 

 which the common tendon sends to the five digits develop 

 sesamoid bones, just before their insertions into the bases of 

 the distal phalanges. The fifth digit has its abductor, flexor 



