THE COD. 95 



sends off backwards a long process which fits into a deep 

 notch in the frontals. 



36. The parethmoids (p.e\ irregular paired bones 

 forming large lateral projections at the anterior end of the 

 brain-case, representing ossifications of the olfactory capsules. 

 Each presents on its outer surface an articular cavity (jf) for 

 the palatine ( 46). 



37. A vacuity on each side between the mesethmoid, 

 the parethmoid, and the frontal, and serving to lodge the 

 nasal sac ( 180). 



38. The absence of side walls to the skull except in the 

 olfactory and auditory regions. 



39. A longitudinal section shows that in the dried skull 

 there is free communication between the cavity for the brain 

 and those for the auditory organs. 



VIII. In each side of the upper jaw and suspenso- 

 rium make out 



40. The hyomandibular (/im), a large bone articulat- 

 ing with the facet (y) afforded by the sphenotic and pterotic 

 by a prominent rounded head (y) : it sends off a long 

 backward process for articulation with the opercular, 

 and presents on its outer surface a prominent, down- 

 wardly directed ridge serving for muscular attachments, 

 and perforated anteriorly by two foramina for the seventh 

 nerve. At its lower end the hyomandibular ends in 

 front in a jagged triangular process, behind in a straight 

 edge. 



41. The symplectic (sy), a long, somewhat triangular 

 bone, having a short dorsal edge united by synchondrosis 

 with the straight lower border of the hyomandibular, and a 

 pointed ventral process which fits into a groove on the inner 

 face of the quadrate ( 42). In the natural position of the 

 bones, the symplectic, as well as a considerable portion of 



