SYNOPSIS OF THE SPEOTES OF DOLPTTINS. 



1. ARTIFICIAL KEY TO THE GENEllA, BASED ON EXTERNAL CHARACTERS. 



Head with a beak which is usually distiuctly marked off ft-oin the forehead by a con- 

 strictiou. 



Dorsal fin absent <">. Tnrsio. 



Dorsallin present; triangular or ovate. 



r>eak not distinctly marked off from the forehead 10. <'iphnJoyJi\nichus. 



Dorsal iiu present ; falcate. 



Lmjcnorhtitivlnis, 

 Beak distinct, short and rim-liko { ?8. Saijmatiafi* 



S7. Lagvn 

 ?9. Ftre 



Beak distinct, elongated. 

 Symjihysis of mandible long. 



Crowns of teeth rugose 2. Stcuo. 



Crowns of teeth smooth 1. Sotalia sps. 



Symphysis of mandible short. 



( 3. T«rsiOj).s. 



Sides without longitudinal bands of color < 1. Sntalia h])h. 



I 5. Vrodi'lphinxa sps. 



Sides w ith longitudinal bands of color | ^^; ^/^IjHlii^^.s sps. 



Head without a beak, or with merely au obtuse ridge margining the upper jaw. 

 Crowns of teeth compressed, spade-shaped. 



Dorsal iiu absent 11. Ncomeris. 



Dorsal fin present, triangular or slightly falcate 12. Plwcwna. 



Teeth conical, nearly or (juite ujiright in the jaws. 

 Teeth in upper jaw deciduous ; mandibular teeth few, confined to the region of 



the symphysis 14. Grampus. 



Teeth persistent in both jaws. 



Pectoral fins very long and narrow ; teeth confined to the anterior half of the 



rostrum 15. Globkcphalus. 



Pectoral fins broad, ovate ; dorsal fin very high and prominent (especially in 



the male), size large 1~- Orca. 



Pectoral lius moderate, falcate. 



Teeth few and large; color black; size large. Pelagic K'. Psciidorca. 



Teeth small ; color bluish-gray. Fluviatile i:^- OrceUa. 



Teeth irregular and implanted obliquely in the jaws. 



Pectoral fins broad, dorsal fin rudimentary; color white... 18. Dvlphinapteviis. 

 Teeth wanting (i. e., tusks concealed in the female), or present in the form of a 

 single, very long, straight, spirally grooved tusk (t. e., righttusk con- 

 cealed in male; rarely both right and left developed). 19. Monodon. 



* Known only from skulls. 



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