288 MESSRS. B. C. A. WIXDLE AND F. Q. PARSOXS OX [NoV. 3, 



says that the costal origins do not interdigitate with the tra.ns- 

 versalis. 



Ohliquus abdommis externus.—T\\is muscle usually rises from a 

 large number of ribs, as the following list shows : — 



Hippotamus(l) 4-15 



Pig(ll) 7-13 



Chevrotain (20, 22) 6-13 



Sheep(43) 6-13 



Harnessed Antelope (55) 5-1 2 



Duiker-bok (54) 6-14 



Tapir(62) 4-18 



Horse (63) 4-18 



Hyrax(75) 5-22 



Elephant (81) 3-19 



Elephant (72) 3-20 



The insertion into the crest of the ilium is very slight, so that 

 Poupart's ligament is not a well-defined structure as in Man. 

 In the Horse the external abdominal ring is a large oval structure, 

 but in the Ruminants it is a mere slit, the two pillars joining at 

 the pubic attachment. The muscle is largely supported by the 

 tunica elastica which lies superficial to it and is specially well- 

 developed in the Solipeds, Ruminants, and Elephant. 



The Supracostcdis is the forward continuation of the external 

 oblique ; we have little doubt that it is always present in Ungulates, 

 although it is so thin and transparent that it requires careful 

 looking for, and many authors make no mention of it. It rises 

 from the sternum opposite the second and third ribs and passes 

 forward and outward, covering the anterior par-t of the rectus to be 

 inserted into the first near the junction of the bone and cartilage. 



Ohliquus abdominis internus. — This has a definite origin from 

 the iliac crest and lumbar aponeurosis ; it is much moi'e fleshy in 

 the hinder than in the fore part of the abdomen and is insei-ted 

 into the cartilages of the hinder libs. Myocommata are frequently 

 found extending into it. 



Retractor ultimce costce. — Chauveau (II.) describes in the Horse 

 a small oblique muscle lying dorsal to the quadratus lumborum, 

 rising from the anterior lumbar costal processes and being inserted 

 into the posterior border of the last rib ; he regards this as part of 

 the internal oblique sheet, and we have little doubt that he is right 

 since it is entirely in series with the internal intercostals. We 

 have found the muscle in the Cervidee, Bovidfe, and Tragulidse, and 

 believe that it is present in all Ungulates (see text-fig. 27, H., 

 p. 287). 



The Transv&rsalis abdominis requires some little care to 

 separate from the internal oblique, but, unlike that muscle, it is 

 more fleshy in the anterior part of the abdomen, and is usually 

 attached to the deep surfaces of about half the ribs — in the Chevro- 

 tain and Harnessed Antelope to the last six, in the Tapir and 

 Horse to the last eleven. 



