Chap. VIII.] 



THE SKELETON. 



145 



the chamber is formed by the frontals posteriorly, and the 

 nasal a (45, na.) anteriorly. In front are the openings of the 

 external nares, bounded below by the pre-maxilla^ (p. mx. ), which 

 send up long ascending processes (n. p.} to form part of the 

 outer wall of the nasal chamber. This outer wall is completed 

 by the maxilla? (mx.), which are spongy in structure, and by the 

 lachrymals (k.), which are apt to drop out in a dry skull, as in 

 Fig. 45. Each is perforated for the lachrymal duct. The incom- 

 plete floor is formed by the horizontal wings of the vomers and 

 by the upper horizontal laminae of the palatines. 



The olfactory chamber is filled with a spongy mass of bone 

 of threefold origin, and com- 

 posed of (1) a superior pouchlike 

 process of the 4 nasal, the naso- 

 turbhial ; (2) a median mass 

 ankylosed with the mesethmoid, 

 and in the adult with the vomer- 

 ine trough, the ethmo-turbinals or 

 parethmoids; and (3) an anterior 

 scroll-like mass in close con- 

 nection with the maxilla? the 

 maxillo-turbinals. All these tur- 

 binal bones are covered over in 

 the living rabbit with mucous 

 membrane. That covering the 

 ethmo-turbinals is supplied by 

 the olfactory nerve, while that 

 investing the maxillo-turbinals 

 is innervated by a branch of 

 the fifth. 



Connected with the Olfactory Posterior palatal foramen, pa.p.mx. Palatal 



chambers are the narial passages process / maxilla - * * *" Palatal 



. r process of palatine, pa. p. pr. Palatal pro- 



(1 Ig. 46), 01 Which the VOmers, cess of pre-maxilla. pa. Palatine, pt. 



pre-sphenoid (p. s.), and part of ptei> yg id - *>* P- Pterygoid process of 



1 A . .- r ali-sphenoid. p. s. Pre-sphenoid. 



the basi-sphenoid (o. s.), form the 



mid-line of the incomplete roof. The maxillae (mx.), palatines 

 (pa.), and the ptery golds (pt.\ which are in relation with the 

 10 



FIG. 46. - PALATE OF RABBIT (viewed from 

 under side). 



a. p. J. Anterior palatine foramen. 

 &. s. Basi-splienoid. mx. Maxilla, mx. p. 

 Maxillary process of pre-maxilla. p. p. f. 



