324 BULLETIN OF THE UNITED STATES FISH COMMISSION, 



rows of scales. Head brownish, unspotted. A large, distinct, round 

 blackish blotch on end of caudal xjeduucle and base of caudal fin, more 

 distinct than in other species known to us. A distinct bluish black 

 vertical bar on lower anterior part of opercle, partly concealed by angle 

 of preopercle. Fins all bright yellowish; ventrals and anal not dark. 

 Peritoneum dusky. 



This small species was found to be rather rare at Mazatlan, and com- 

 paratively abundant at Panama. 



Dr. Steindachner has identified this species with Hccmulon caudima- 

 cula C. and V., remarking: " Ich verglich die bei Acapulco gesammel- 

 ten Exemplare auf sorgfaltigste mit jenen, welche das Wiener Museum 

 aus der Bucht von Eio Janeiro, von Eio Grande do Sul sowie von IMa- 

 rauhao besitzt, uud bin uicht in Stande, zwischen diesen ein Artun- 

 terschied zn entdecken." 



Whether the Brazilian specimens referred to really belong to the ])res- 

 ent species or not, it is evident that the original Hcmndon caudimacula 

 is a very different species. 



The species of Diabasis found on the Pacific coast of Tropical Amer- 

 ica may be compared as follows : 



a. Scales above lateral line arrauged in very oblique rows. 

 b. Spots on scales black or blackish. 



c. Snout long and protruding, forming more than two-fifths length of bead ; 

 preorbital very deep, wider than eye ; sides with dark vertical bars ; 



sides of head spotted : size large Sexfasciatus.* 



cc. Snout short and bluutish, about one-fourth length of head ; preorbital 



about as wide as eye; sides not barred; head unspotted ScuDDEUi.t 



hb. Spots on scales pale-bluish or grayish. 



d. Mouth large, nearly horizontal, the maxillary extending to opposite 

 middle of eye, beyond jireorbital sheath; head long, 3 in length: 

 gill-rakers short and weak ; anal fin rather high, the first soft rays 

 when depressed extending beyond the base of the fin ; spots silvery, 



comparatively large Steindachxeki. 



dd. Month small, oblique, the maxillary reaching pupil, not beyond pre- 

 orbital sheath; head short, 3| in length ; gill-rakers comparatively 

 long and slender; anal fin low, the first soft ray when depressed not 

 reaching to base of last ray; spots bluish, small, stellate. 



Flaviguttatus. t 



* Hcemulon sexfasciatus Gill, Proc. Ac. Nat. Sci. Phila. 1862, 254: Hwmulon macnlosnm 

 Peters, Berlin Monatsber., 1869 705. Cape San Lucas {Gill); Mazatlan {Gilb. Peters); 

 Panama {Steind. Gilb.). 



i Hcvmalon scudderi Gill, Proc. Ac. Nat. Sci. Phila., 1862, 253: II(x;mnlon breviros- 

 trnm Giinther, Fish. Ceutr. Amer. 1866, 418: Hcvmulon undccimale Steindachner, 

 Ichthyol. Beitr. iii, 11, 1875. (Cape San Lucas (GiU); Mazatlan (Stcivd. Gilb.); 

 Acapulco (Steind.); Panama (Gi7«//(er, Steind. Gilb.). The dorsal sx)ines in this species 

 are normally 11. 



X Hamulon flaviguttatus Gill, Proc. Ac. Nat. Sci. Phila. 1862, 254: Hccmulon mar/jari- 

 ti/erum Giinther, Proc. Zool. Soc. Loud. 1864, 147. (Capo San Lucas (Gill); Mazatlan 

 (Steind. Gilb.); Acapulco (Steind.); Altata (Steind.); Panama (Gthr. Steind. Gilb.). 



