516 



ZOOLOGY 



SECT. 



not meet in the middle line above in most Cetacea, being separated 

 by the supra-occipital (SO.) and an inter-parietal (IP.) ; there is 



thus no sagittal suture. 

 A large supra-orbital 

 plate is developed from 

 the frontal. There are 

 large and stout zygo- 



cist 



FIG. 1159. Pes of Armadillo 

 (Dasypus sexcinctus). ast. astra- 



FiG. 1158. Pelvis and sacrum of Armadillo (Dasypus gains ; caL calcaneum ; cbd. 

 sexcinctus). ac. acetabulum ; il. ilium ; isch. ischium ; cuboid ; ect. ecto-cuneiform ; 

 obt.for. obturator foramen ; pect. tub. pectineal tubercle ;. ent. ento-cuneiform ; mes. meso- 

 pub. pubis. cuneiform ; nav. navicular. 



matic processes of the squamosal, but the jugals are extremely 

 smalh \ In all the recent forms the maxilla (Mx.) is very large and 

 extends backwards, to overlap a good deal of the frontal, and for- 

 wards nearly to the extremity of the snout ; while the premaxillaB 

 (P. MX.), which are long narrow bones, bound but a very small 

 part of. 'the oral border of the upper jaw. The nasals (Na.) are 

 very A small. The tympanic bone is very large, and is some- 

 times fused with the periotic (Mystacoceti), sometimes not 

 (Odontoceti). The lower jaw is remarkable for the absence of an 

 ascending ramus. 



The scapula in most of the Cetacea is very broad and flat, ex- 

 panded into the shape of an operi fan. The spine is usually situated 

 close to the anterior border, sometimes coalescent with it. The 

 acromion is curved and flat, the coracoid also compressed and parallel 

 with the acromion. In some, both acromion and coracoid are 

 absent. There is never any trace of a clavicle. The humerus is 

 short and very stout ; the head freely movable in the glenoid cavity ; 

 the distal articulating surfaces are flat and oblique, meeting at an 

 angle. The proximal ends of the radius and ulna are so firmly 

 united with the humerus as to allow of very little movement ; 

 at the distal end there are no complete sy no vial membranes. The 



