10 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I ID 



the former was selected as the genotype. A comparison of the type 

 material of the two species, in fact, has revealed only minor differ- 

 ences, which are shown in the following parallel comparison : 



N. cubanus N. tropicus 



Anal fin rather short, with 39 to 43 Anal fin somewhat longer, with 43 to 

 rays, its base 2.55 to 3.0 in standard 48 rays, its base 2.25 to 2.8 in stand- 

 length, origin of fin usually equidis- ard length, origin of fin usually equi- 

 tant from anterior margin of eye and distant from posterior margin of eye 

 base of caudal. and base of caudal. 



Dorsal fin rather short, with 13 or Dorsal fin slightly longer, with 14 to 



14 rays, its origin slightly more than 16 rays, its origin scarcely an eye's 



an eye's diameter behind origin of diameter behind origin of anal, and 



anal, and about equidistant from about equidistant from posterior 



margin of opercle and base of caudal. margin of eye and base of caudal. 



Gill rakers 17 to 19 on lower limb of Gill rakers 18 to 21 on lower limb of 



first arch. first arch. 



This, then, is another instance of the rather common occurrence of 

 "twin" species in the tropical Atlantic and Pacific. Such closely re- 

 lated species generally have been found on the opposite coasts of 

 Panama. However, as the West Indian (Cuban in this instance) and 

 the Atlantic Panamanian faunas are largely identical, cuhanus may 

 be expected on the Atlantic coast of Panama and the neighboring 

 countries. 



Family SYNODONTIDAE 

 SYNODUS CINEREUS, new species 



Figure 5 



Trachinocephalus myops Bean (not of Schneider), Fishes in "The Bahama 

 Islands," Geogr. Soc. of Baltimore, 1905, p. 297, Bahama Islands. 



Head 4.0, 3.9 ; depth about 6.1, 7.2 (not accurate because of distor- 

 tion) ; D. 12, II ; A. 9, 9 ^ ; P. 12, 13; scales 57, 60, before dorsal 

 20, 21. 



Body about as broad as deep at insertion of ventral fins, caudal 

 peduncle deeper than broad, 4.1, 4.5 in head ; head nearly as broad as 

 deep, its upper surface posterior to interorbital with bony ridges; 

 upper anterior rim of eye with coarse serrae ; snout broader than long, 

 5.0, 5.6 in head; eye 4.3, 5.6; interorbital concave, 15, 9.7 in head; 

 mouth large, premaxillary extending far beyond eye, 1.75, 1.7 in head ; 

 mandible rounded, without fleshy knob, included in upper jaw ; lateral 



1 The last double ray of the dorsal and of the anal was counted as one. 



