5. PRODELPHINUS P. C.^RULEO-ALBUS AND EUPHROSYNE. 163 



Head with a distiuct elongated beak. Dorsal and pectoral fins fal- 

 cate (Itbe former triangular in P. frwnatus). Color black or gray 

 above, light below, with spots or longitudinal bands. 



PRODELPHINUS C^RULEO-ALBUS (Mcycu). 

 (Plate 14, figs. 1 and 2.) 



Head rounded and much arched. Snout very flat, longer than in D. 

 delphis and less compressed; lower jaw protruding a little beyond the 

 upper jaw. Pectoral and dorsal fins pointed and not deeply eraargi- 

 nate behind. 



Teeth ||, conical, pointed, and curved inward. Vertebra',: C 7; 

 D. 14; L. and Ca. 52+. Skull similar to that of P. eiiphrosyne, but 

 with small temporal fossie, which are directed upward. 



Back and forehead dark steel blue. A very dark blue stripe starts 

 from the dorsal fin, and, jiassing forward, ends abruptly in front. A 

 narrow blue stripe on the sides from the eye to the vent, expanded at 

 the posterior end. Pectoral fin blue-gray, connected by a colored band 

 with the ring which surrounds the eye. Belly, snout, and other parts 

 of the body white. ( Meyen . ) 



Rahitaf. — Coast of South America, near the mouth of the Kio de la 

 Plata. 



PRODELPHINUS EUPHROSYNE (Gray). 

 (Plato 15, figs, laud 2.) 



Body robust; snout long; dorsal fin high and falcate; pectoral fins 

 small. 



Upper parts black; sides blackish; margins of the jaws blackish, 

 their extremity entirely black; throat and belly white; circumference 

 of the eye black. A narrow black baud (broadest at the extremities) 

 from the eye to the vent, with a branch given oft' above the base of the 

 pectoral fins and running a short distance downwards and backward, 

 A band of white, broadest in the middle, separates the lateral black 

 band from the dark color of the sides above; another and broader 

 black baud extends from the eye to the base of the pectoral fin and has 

 along its center a white area which communicates with the white of the 

 throat immediately below the eye. Fins black, with a narrow line of 

 white on their anterior margin (sometimes absent). 



Teeth J|- Vertebra: C. 7; D. 15; L. 22; Ca. 32 = 7G. 



Measurements of the exterior, — Total length (on the curv^es), 209.7""; 

 tip of beak to the anterior base of the dorsal fin, 93.2""; breadth of 

 flukes, 42'='" ; length of an terior margin of pectoral fin, 30.5'='". ( Pucherau : 

 I), marginatns.) 



Measurements of the skull. — [Mas. cVRist.nat. Type of i). margina- 



