1903.] 



THE MUSCLES OF THE UNGULATA. 



269 



rises outside. Our reasons for coming to this conclusion are, 

 firstly, that in dissecting away the obturator externus to expose, 

 as we thought, the obturator tertius we found that the two 

 muscles were practically one, and that no division was possible 

 between them ; secondly, that the obturator membrane can be 

 clearly seen on the pelvic surface of the so-called obturator tertius ; 

 and, thirdly, that the part of the muscle which passes through 

 the obturator foramen is supplied by the obturator nerve, and not 

 by a branch from the sacral plexus. This last fact is perhaps the 

 one on which we are inclined to lay most stress. We regret that 

 in many of the animals which passed through our hands we did 

 not pay enough attention to this muscle, and it was only when 



Text-fig. 25. 



to behind l£ss,'5 troche. 

 = Quad .tubi;:? 



X 



Hip-region of Sheep, showing double Quadratus femoris muscle. 



G.MED. Gluteus medius. 

 G.MiN. Gluteus miniinus. 



O.I. Obturator interims. 

 O.E. Obturator externus. 



working through Hyrax with the aid of Mivart and Murie's 

 paper that we first noticed it. We have seen enough, however, 

 to feel sure that it is present in the Suid^e, Tragulidse, Giraffidte, 

 Bovidse, and Procaviidfe. We expect, from what we know of 

 other muscles, that it will also be found in the Hippopotamidse, 

 Camelidse, and Cervidte, if carefully and specially looked for, but 

 the various writers on these families were, like ourselves, evidently 

 ignorant of its existence. With regard to the Perissodactyla, we 

 have satisfied ourselves, through the kindness of the authorities at 

 the Royal Veterinary College, that no muscle passes through the 



