5(jG 



Mr. C. T. Regan on the 



F\g. 2. 



PJVT 



^mx jy 





A. Arges lieterodon. P. NematOf/enys inermis. C. Diplomi/sfex jynpH- 

 lostis. D. Chaca lophioides. Head-skeleton seen from above. 



pmx, prsemaxillary ; mx, maxillary ; mn, lower jaw ; w, nasal ; pal, pala- 

 tine; WIS, mesopterygoid ; mt, metapterygoid ; q, quadrate; hn, 

 hyomaudibular ; jyop, praeoperculum ; op, operculum ; top, inter- 

 operculum ; eth, mesethmoid ; leth, lateral ethmoid ; f, frontal ; 

 spo, sphenotic ; pto, pterotic ; epo, epiotic ; soc, supraoccipital ; eoc, 

 exoccipital ; pt, post-temporal ; scl, supra-clei thrum ; p, parapophysis 

 of fourth vertebra ; p' , parapophysis of fifth vertebra j r, rib of sixth 

 vertebra ; n, nuchal plates. 



