390 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



Genus HYPSOBLENNIUS Gill, 1861 



Body elongate, compressed; head short, blunt; mouth small, hori- ^ 

 zontal; maxillary rarely extending beyond middle of eye; teeth in the 

 jaws in a single close-set series, not freely movable; no canines; gill 

 membranes broadly united to the isthmus, the gill openings being 

 restricted to the sides, but extending downward to or beyond middle 

 of base of pectoral; lateral line generally incomplete; scales wanting. 



As a result of the great changes in the structures about the head, 

 which take place during development in some, if not all, the species 

 of this genus, a few genera based on juvenile characters apparently 

 have been proposed. The young of at least some of the species have a 

 prominent supraocular bony ridge (making the interorbital broad and 

 flat), which is lost with age. They also have one or more spines along 

 the margin of the preopercle, which are lost. The caudal fin is often 

 if not always concave in juveniles, and convex in adults; the pectoral I 

 fins commonly are black and there is a series of prominent black spots 

 along the base of the anal. The changes occurring during develop- 

 ment in H. hentz, a species from the Atlantic, ranging from Chesapeake 

 Bay to Florida, have been described in detail by Hildebrand and 

 Cable (1938, pp. 576-589). As already suggested by Norman (1943, 

 p. 802), Spinoblennius Herre (1935), with S. spiniger as the type, of 

 which a paratype is before me, quite surely is a juvenile of this genus. 

 The same applies to Hypsoblenniops Schultz (1942), with H. rickettsi 

 as its type, of which several paratypes are now before me. 



Two and possibly three species come within the scope of the present 

 work. 



KEY TO THE SPECIES 



a. A shallow groove across head behind eyes; gill opening not extending across 

 lowermost ray of pectoral; orbital tentacle longer than eye. 



paytensis (p. 390) 

 aa. No groove across head behind eyes; gill opening extending below lowermost 

 ray of pectoral. 

 b. Dorsal with 16 or 17 soft rays; anal with 20 or 21 rays; orbital tentacle 



shorter than eye robustus, new species (p. 391) 



bb. Dorsal with 14 to 16 soft rays; anal with 18 to 20 rays; interorbital broad, 

 flat, 4.0 to 4.6 in head species? (juveniles) (p. 393) 



HYPSOBLENNIUS PAYTENSIS (Steindachner) 



Btennius (Hypleurochilus) paytensis Steindachner, 1876, p. 171, Paita, Peru 



(original description). 

 Hypleurochilus paytensis Stark s, 1906, p. 800, Paita, Peru (number of dorsal 



and anal rays stated for two specimens, but no description offered). 



Head 4.0; depth about 4.5; D. XII, 17; A. 21; P. 14. 



Head with a shallow groove behind eyes; snout short, high, steeper 

 in adults than in young; eye 4.0 in head; interorbital concave, half or 

 a little less than half diameter of eye; maxillary reaching past anterior 

 margin of eye; no posterior canines; nasal tentacle short, fringed; 



