170 CRETACEOUS AND TERTIARY FISH. 



spines or serratures. Gill-openings wide, gill-membranes not 

 united, free from isthmus. Gills 4, a slit behind fourth. Gill- 

 rakers very short or obsolete. Pseudobranchise well developed. 

 Branchiostegals 7. First superior pharyngeal not present, sec- 

 ond, third and fourth separate, with teeth. Lower pharyngeals 

 separate. Air-vessel large, bifurcate anteriorly. Many pyloric 

 cceca. Vertebras 24. Body covered with small cycloid scales. 

 Head scaly above on sides. Lateral line well developed, straight. 

 First dorsal over ventrals, of 5 rather stout spines. Second 

 dorsal remote from first dorsal, similar to anal and opposite to it. 

 Caudal forked. Pectorals short, placed in or below line of axis 

 of body. Ventrals I, 5, abdominal, in advance of middle of 

 body. 



Usually a single genus, Sphyrcena, is allowed, but, according to 

 Hay, Dictyodus is admitted. 



Genus DICTYODUS Owen. 



Dictyodus Owen, Rep. Brit. Assoc. Adv. Sci., 1838, p. 142. No species given. 



Type Dictyodus destructor Owen, Cat. Foss. Rept. Pise. Mus. Roy. Coll. 



Surg., 1854, P- 161. 

 Sphyrccnodus Agassiz, Poiss. Foss., V, pt. 1, 1844, p. 98. Type Sphyrcenodus 



priscus Agassiz, first species, restricted by Woodward, Cat. Foss. Fishes, 



V, 1901, p. 473. 



Teeth moderate, compressed, and each side with sharp keel, 

 often finely serrated. Apex sometimes notched. 



Scarcely distinguished from Sphyrama, and known only from 

 fragmentary jaw and teeth. Only two species, described below. 

 Woodward refers this genus to the Scombridce. 



Dictyodus silovianus (Cope). 



SpJiyrccnodus silovianus Cope, Proc. Amer. Philos. Soc. Phila., XIV, 1875, 



p. 362. Miocene of Cumberland Co., N. J. 

 Dictyodus silovianus Hussakof, Bull. Amer. Mus. N. H., XXV, 1908, p. 71, 



fig- 37 (type). 



Fragment of jaw with five teeth and alveoli for four others. 

 Jaw compressed and slightly curved, with smooth surface. Teeth 

 subequal, compressed, rather short and acute, without roots, and 



