426 THE ANATOMY OF VEBTEBEATED ANIMALS. 



and the latter ankyloses with the vomer on each side. 

 The inferior, or maxillary, turbinal is extremely large and 

 complicated, and it blocks the nasal passage in front of the 

 others like a sieve, or strainer. There is no lachrymal 

 bone, but the jugal is large. The squamosal is ankylosed 

 with the periotic and tympanic. The latter is massive and 

 shell-shaped, somewhat as in the Cetacea, but it has rather 

 different relations to the auditory meatus. The periotic 

 is veiy large, and its tumid pars mastoidea appears largely 

 on the exterior of the skull. The fossa under the superior 

 vertical semicircular canal is prolonged into this tumid 

 part of the periotic. 



The alveolar portions of the premaxillse are very small, 

 but these bones extend far up the sides of the anterior 

 nares. The maxillae do not extend over the frontals. The 

 mandible has a well-developed coronoid process. 



The poUex is the longest and strongest digit, the others 

 gradually decreasing in length. The fifth metacarpal arti- 

 culates with the cuneiform bone, as well as with the unci- 

 form. 



The ilium is short, and the long pubis and ischium are 

 greatly inclined backwards, so that the long diameter of 

 the OS innominatum makes only an acute angle with the 

 spine. The femur is much shorter than the humei-us. 

 The tibia and fibula are ankylosed, and more than twice as 

 long as the femur. The pes is longer than the tibia. The 

 astragalus has a peculiar, roof- shaped, tibial surface, and 

 sends a process backwards which contributes to the forma- 

 tion of the very short heel. The hallux is the strongest 

 of the digits ; while this and the fifth digit are the longest 

 of those of the pes. 



The cutaneous muscle is largely developed and inserted 

 into the humerus. The pectoralis major is very large, and 

 arises from each side of the prolonged manubrium, and 

 even in front of it, beneath the neck; the fibres of the 

 muscles of opposite sides are continuous. The palmaris 

 longus is a strong muscle, but the proper digital muscles are 

 weak or absent, as in the case of the abductor, adductor, 



