HOLOCEPHALI 



(Fig. 114). Ganodus, Ag. ; Jurassic, England. Ischyodus, Eg. ; Jurassic 

 and Cretaceous, Europe and New Zealand. Elasmodectes, Newt. ; Creta- 

 ceous, England. Elasmodus, Eg. ; Eocene, Europe (Fig. 141, G). 



Fio. 142. 



Restored mandible of Myriacanthus. (After Dean.) j, jaw ; pi, dermal plate ; 

 pst, presymphysial tooth ; t, mandibular tooth. 



Family RHINOCHIMAERIDAE. The proboscis is very long and pointed. 

 Narrow calcined rings are present round the notochord, the clasper is 

 long but of simple structure, the olfactory bulbs are remote from the 



FIG. 143. 



CdLlorhyncJius antarcticus, Lac. (After Garman, from Dean.) A, dorsal aspect ; B, ventral 



view of head. 



cerebrum, and the lateral-line canal opens only by a very narrow slit. 

 The teeth have cutting edges, but no tritors in Rhinochimaera ; and 

 tuberculated tritors in Harriotta (Fig. 141, F). 



Rhinochimaera, Qannan, and Harriotta, G. and B. ; Pacific (Fig. 145). 



