534 



ZOOLOGY 



SECT. 



is deposited. In the toothed 

 Whales the carpals are com- 

 pletely ossified, and are of poly- 

 gonal form : the phalanges are 

 also ossified, with incomplete 

 synovial articulations. In the 

 Cetacea there are sometimes 

 five digits, sometimes only four : 

 more or fewer have considerably 

 more than the normal number of 

 phalanges — sometimes as many 

 as fourteen. The second digit is 

 usually the longest. 



Yestiges of the pelvis are pre- 

 sent in the form of a pair of long 

 narrow bones (Fig. 1148, pelv.) 

 which lie parallel with the spinal 

 column some little distance be- 

 low the region where the chevron 

 bones begin : these appear to re- 

 present the ischia. A second 

 pair of smaller bones which lie 

 close to these in the Whale-bone 

 Whales ai-e apparently vestiges 

 of the femora, and there may be 

 additional vestiges representing 

 the tibia^. 



Skeleton of Sirenia. — In the 

 Sireuia (Fig. 1151) the cervical 

 vertebra? do not coalesce, with 

 the exception of two of them in 

 the Manatee. In the Manatee 

 there are only six cervical ver- 

 tebrae, and the neural arches are 

 sometimes incomplete. In the 

 trunk the thoracic vertebrae are 

 numerous; all have distinct 

 facets for the heads of the ribs, 

 and well developed zygapo- 

 physes. The caudal vertebrae 

 are numerous and depressed, 

 with wide transverse processes 

 The ribs are numerous, but few 

 of them are connected with the 

 sternum. The sternum is a broad 

 bone not composed of distinguish- 

 able segments. 



