THE EDENTATA LORICATA. 289 



The skull has a complete zygoma and well-developed pre- 

 inaxillas. The lachrymal bone is large, and the lachrymal 

 foramen is situated upon the face. The tympanic bone is 

 annular, and the periotic mass so large, and enters so much 

 into the lateral walls of the skull, as to remind one of its pro- 

 portions in the Sauropsida. The mandible has an ascending 

 ramus. The clavicules are complete. 



The jaws are provided with teeth, the substance of which 

 IS traversed by a great number of parallel vertical canals. 

 These teeth are rootless molars, and the greatest number 

 which has been observed is j.*, but the small anterior ones 

 fall out, reducing them to ~^. The hindermost, and the small 

 anterior ones, are simple cylinders, but the middle teeth pre- 

 sent a longitudinal groove on each side. 



The submaxillary glands are very large. The stomach is 

 divided into a right and a left portion ; the former having very 

 thick and muscular walls. The intestine has a cascum. It is 

 stated that the ductus arteriosus long remains open. 



The two uteri open separately into the vagina. The pla- 

 centa is deciduate and discoidal. 



d. In the Loricata, the dorsal region of the body is covered 

 by a carapace, composed of epidermal scales, and of suturally 

 united quadrate, or polygonal, scutes, which are dermal ossi- 

 fications, so that the whole structure is strictly comparable to 

 the dorsal shield of a crocodile. These are the only Mammals 

 in which such scutes exist. When fully developed, the dorsal 

 armor of one of these animals presents five distinct shields, 

 the edges of which permit of a certain amount of motion be- 

 tween them. One of these covers the head, and is called 

 cephalic; another, nuchal, protects the back of the neck; a 

 third, scapular, covers the shoulders like a great cape ; a fourth, 

 usually consisting of a number of tree and movable segments, 

 covers the posterior dorsal and lumbar region, as the thoraco- 

 abdominal shield; and the fifth, tYie pelvic, is attached by its 

 deeper surface to the ilia and ischia, and arches over the rump 

 like a half dome. The tail may further be invested by a series 

 of incomplete bony rings and scattered scales ; and scutes are 

 distributed over the limbs. In one genus, Chlamydophorus, 

 the scutes are developed only in the pelvic region. 



In the skull the premaxillee are well developed, and the 

 zygoma is complete. The mandibular ramus usually has a 

 well-developed ascending portion and coronoid process. 

 Clavicles are present. The fore- and the hind-feet rest upon 



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