346 



TELEOSTEI 



parethmoid) and post-frontal (sphenotic), and even the pterotic 

 (' squamosal '), may thus become converted into entirely cartilage 

 bones. The parietal region often becomes grown over by the 

 trunk myotomes from behind (as in the Gadidae, Fig. 328), and 

 the supraoccipital then develops a vertical crest. The muscles 

 may simply cover the parietals or they may project into a post- 



.1 pmx 



ptc 



pa- 



epc 



spt 



FIG. 3:27. 



Dorsal view of the skull of Cyprinvs earpio, L. A dotted line indicates the lateral-line 

 canals on the left side, epo, epiotic ; eth, pre-ethmoid (rostral) ; /c, frontal ; I, lachrymal ; 

 meth, inesetlnnoid ; inx. maxilla ; op, opercular ; pa, parietal ; pal, palatine ; pf, prefrontal ; 

 pmx, premaxilla ; pop, preopercnlar ; ptf, postfrontal ; pto, pterotic ; nob, supraorbital ; 

 soc, supraoccipital ; spt, suprateniporal ; st, anterior supratemporal. 



temporal foramen, as in Amia, tending to separate the parietals from 

 the cranial wall. This post-temporal fossa is often present in the 

 lower families (Elopidae, Albulidae, Osteoglossidae, Clupeidae, etc.). 

 It may be roofed over by the epiotic and pterotic as well as the 

 parietal. A supratemporal (extrascapular) is often present, but is 

 lost in the higher sub-orders (Figs. 329-31). 



The position of the parietals is important. It may safely 



