FISHES OF CEARA, BRAZIL JORDAN AND BRANNER 2$ 



The species is apparently new. On the characters at hand it is 

 separable from Elopopsis by the form oi the small teeth on the pos- 

 terior part of the mandible, the presence of sharp subequal teeth on 

 the maxillary, and by the relative size of other teeth. This may be 

 held to indicate generic difference. In Pachyrhisodus the teeth of the 

 mandible are subequal and close-set. The type of this species is in 

 the possession of Senhor da Rocha at Ceara ; the broken counterpart 

 is in the geological collections at Stanford University. 



The genera of Brazilian Cretaceous Elopidas may be thus compared 

 with the living genera: 



a. — Eloping: Pseudobranchiae large (in living species); scales relatively 

 small ; last ray of dorsal not prolonged ; anal smaller than dorsal ; base 

 of caudal more or less scaly. 

 b. — Dentition even, the teeth slender and close-set ; dorsal with a sheath of 

 scales. 

 c. — Ventrals inserted behind middle of dorsal. 



d. — Lateral line well developed; teeth small Calamopleurus 



dd. — Lateral line obsolete or developed on the anterior scales only. 

 e. — "Parietals not separated by the supraoccipital" ; scales 



entire or nearly so Notelops 



ee. — Parietals separated by the supraoccipital ; scales crenate. 



Rhacolepis 

 cc. — Ventrals inserted under first ray of dorsal ; lateral line well de- 

 veloped; body elongate; teeth small, even Slops 



bb. — Dentition uneven, some of the teeth large, robust canines Enneles 



aa. — MEGALOPiNiE: Pseudobranchiae none; scales large, firm; anal fin larger 

 than dorsal; last ray of dorsal produced in a long filament; postorbital 

 bones very thin, membranaceous. 



e. — Dorsal fin inserted above ventrals (cyprinoides) .Megalops 

 ee. — Dorsal fin inserted behind ventrals (atlanticus) .. .Tarpon 



Fig. i6. — Head of Megalops 

 cyprinoides Broussonet. 

 Riu Kiu Islands. 



Fig. 17. — Head of Tarpon atlanticus 

 C. & V. Porto Rico 



