Mammalia. In-Enamellata. 49 



the instances of anchylosis, are somewhat loosely connected together. 

 The Frontals are not confluent. No distinct Nasals are found an- 

 terior to the frontal suture. The Prcemaxillaries of the Dugong 

 ( Halichore) are remarkable for their very large and long deflected 

 alveolar portion. The Zygoma is unusually massive. The Basi- 

 sphenoid coalesces with the Alisphenoids; the Praesphenoid similarly 

 coalesces with the Orbitosphenoids, and is wedged between the 

 laminae of the Vomer as a compressed * rostrum.' 



The Vertebral Column. The Cervical region is short, but longer 

 in proportion than in the Ceto. The cervical vertebrae are 

 generally free {cf. Cete) and short. In the Manatee and in the 

 extinct Rhytina (of Steller) they are hut six in number; thus forming 

 an exception to the generally constant number (seven) of cervical 

 vertebrae. The Ribs of the dorsal vertebrae are massive, and join 

 by cartilaginous haemapophyses the sternum, which in the immature 

 state is made up of two bones. There is no distinction of ' Lum- 

 bar' and 'Sacral' vertebrae. Most of the Caudal vertebrae have 

 long diapophyses and haemal arches. 



iScapular Arch and Appendages. The Clavicles are wanting. The 

 Pectoral pair of limbs alone exist, and their supporting arch is 

 reduced to the Scapula, which has a short Coracoid process. The 

 Humerus has the normal Mammalian character, and a synovial 

 articulation {cf. Cete), with the Eadius and Ulna; the latter of 

 these bones developes an obtuse olecranon. The Phalanges are never 

 more than three in number. 



The Pelvic Arch, The Pelvis assumes the Batrachian condition,* 

 and all appendages to the rudiment of the Pelvic Arch are wanting. 



XIII. IJS^-ENAMELLATA. 



The Skull in the Insect-eating f In-Enamellata is long and slender, 

 these proportions reaching their extreme in the true Ant Eaters 

 (Myrmecophaga), owing to the great development of the facial part. 

 In the Brady podidae, on the contrary, the whole head is proportion- 

 ally small, the facial part of the skull being exceptionally short. 

 The cranial cavity is thronghout this order of small proportional size. 

 The Zygomatic arch culminates in regard to complexity in the Brady- 

 podidae, albeit in the small existing species, as also in the Ant Eaters, 



* The Pelvic bones appear to be entirely wanting in Manatus. 



t The Insect-eatiny In-Enamellata are the edentulous Myrmecophagid(B and 

 the Dasypodidce. 



