SCYLLIOIDEI 



149 



Family Scylliidae. With nasal grooves nearly or quite reaching 

 the mouth, and small sharp teeth. The extinct Mesitcia had calcined 

 rings supporting the lateral-line canal, resembling those of the Holocephali 

 (p. 169, A. S. Woodward [499]). 



Some of the Orectolobinae are adapted to a bottom-living habit ; the 

 rostrum is reduced, the head and trunk depressed, and the spiracles 

 enlarged (especially in Eucrossorhinus). 



Km. 100. 

 Cetorhinus maximus, Gun. (From Jordan and Evermann.) 



Sub-Family 1. Scylliinae. Palaeosc yllium, Wagn.; Jurassic, Bavaria. 

 Mesiteia, Kromb. ; Cretaceous, Asia. Scyllium, Cuv. (Seylliorhinus) ; widely 

 distributed, occurs in the Cretaceous strata of Europe and Asia. Pristiurus, 

 Bon. ; European coasts, and Jurassic, Bavaria. 



Fig. 110. 



A, portion of a branchial arch of Cetorhinus (Selache) maximus, Cuv. B, head of a Mackerel, 

 Scomber scomber, L., from which the left operculum has been removed, br, gill-ray; c, cut 

 surface of ceratohyal ; g.a, gill-arch ; g.f, gill-lamella ; i, inner surface of gill-arch ; op, cut 

 >'dge of operculum'; r, anterior gill-raker ; s, outer septum ; t, posterior gill-raker. 



Sub-Family 2. Orectolobinae. Chiloscyllium, M. and H. ; Indian 

 Ocean and Pacific, and Miocene, Europe. Ginglysmostoma, M. H., tropical 

 seas ; and Eocene, Europe and N. America. Steyostoma, M. and H. ; 

 Indian Ocean. Orectolobus, Bon. (Grossorhinus, M. and H.) ; Pacific. 

 Eucrossorhinus, Regan. 



Family Lamnidae. Large sharks without naso-oral grooves, with 

 wide external gill-slits, and with spiracles minute or closed. A lateral 



