THE RABBIT. 277 



anterior to the larynx (see 12 4, 125, p. 289), and always 

 detached in the prepared skull : it consists of a stout thick 

 body, or basi-hyal, a pair of small anterior cornua, or 

 cerato-hyals, and a pair of long, backwardly directed 

 posterior cornua, or thyro-hyals (cerato-branchials). 



VII. Carefully break away in an entire skull the outer 

 wall of the tympanic bone, and make out the 

 following bones : x 



73. The malleus, a small bone, recognised at once by 

 the bony process or manubrium, by which it is attached, 

 in the recent state, to the tympanic membrane. It con- 

 sists of a rounded head, from which the manubrium and 

 other lesser processes are given off, and which presents 

 a saddle-shaped surface for articulation with the incus. 



74. The incus, articulating by a saddle-shaped surface 

 with the malleus, and giving off two processes, the short 

 crus and the long crus. 



75. The os orbiculare, a minute disk of bone attached 

 to the long crus of the incus. 



76. The stapes, a stirrup-shaped bone, having its base 

 inserted into the fenestra ovalis ( 56), and articulated by 

 a small knob on the summit of its arch to the orbiculare. 



VIII. Observe the following points in the teeth : 



77. The incisors, of which two are situated in each 

 premaxilla, and one in each ramus of the mandible. The 

 anterior upper incisors are long, curved, chisel-shaped 

 teeth, covered with enamel on the anterior surface only, 

 marked on the same surface with a deep longitudinal groove, 

 and destitute of roots. The posterior upper incisors are 

 small teeth, situated behind the corresponding anterior 

 incisors. The lower incisors resemble the anterior upper 



1 This may be conveniently done with the skull of a specimen used 

 for dissection. See Sees. XLII XLIII. p. 331. 



