490 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



nearly straight cutting edges, the outside ones with two indentations, 

 making them tricuspid, followed laterally by one to four conical teeth; 

 opercular spine not long; gill membranes united, free from the isthmus, 

 attached to shoulder in front of uppermost ray of pectoral; dorsal 

 and anal small, the former with about 5 to 11 rays, and the latter 

 with about 5 to 9 rays. (The numbers shown in the description include 

 only the rays visible without dissection. Upon cutting the skin at 

 the base of the fins 1 or 2 additional rays become visible.) The origin 

 of the anal a little behind that of the dorsal. 

 A single species is known from Peru. 



ARBACIOSA PYRRHOCINCLA (Cope) 



Figure 93 



Siajases pyrrhocinclus Cope, 1877, p. 27, Peru, precise locality not stated (original 



description) . 

 IGobiesox zebra Regan (not of Jordan and Gilbert), 1913, p. 280, Lobos de Tierra, 



Peru. 

 Arbaciosa hieroglyphica Evermann and Radcliffe, 1917, p. 155, pi. 14, fig. 2, 



Lobos de Afuera, Peru (original description; compared with description of 



A. pyrrhocincla) . — Nichols and Murphy, 1922, p. 513, Paracas Bay, Lobos 



de Afuera Island, Peru. 

 Arbaciosa pyrrhocincla pyrrhocincla Schultz, 1944, pp. 50, 59, Lobos de Afuera 



Island, Peru (diagnosis; synonymy; list of specimens examined). 



Head (to tip of opercular spine) 3.1 to 3.3 ; depth 6.0 to 7.3 ; D. 7 or 8 

 A. 6 or 7; P. 18 to 20. 



Head and body in front of vent depressed; tail compressed; head 

 not quite so broad as long, its width 3.5 to 4.3 in length; caudal pe- 

 duncle 3.4 to 4.6 in head; snout anteriorly rather strongly convex, 

 2.9 to 3.5; eye 4.5 to 6.2; interorbital broad, fiat, without perceptibly 

 raised orbital rims, 3.0 to 4.6; mouth small, its posterior angle well in 

 advance of eye; width of premaxillaries with lip medially two-thirds 

 diameter of eye ; incisor teeth mostly at least with two notches in cut- 

 ting edge, the middle pair broadest and often with smooth cutting 

 edges, the upper series with eight and the lower with six incisors, 

 followed laterally in each jaw by rather strong curved canine; the 

 incisors sometimes in a double series, if so the outer ones rather shorter 

 and prominently notched ; anterior nostril with a very slightly raised 

 margin, and a very small membranous flap behind it; dorsal with 

 strongly convex margin, its longest rays a little longer than snout, 

 its origin generally somewhat nearer vertical from tip of opercular 

 spine than margin of caudal; distance from snout to dorsal 1.2 to 1.4 

 in length; distance from original or dorsal to base of caudal 3.6 to 4.1 

 in length; caudal with broadly convex margin, scarcely as long as head 

 without snout; anal similar to dorsal, though somewhat smaller, its 

 origin a little behind that of dorsal, and rather less than half as far 

 from vent as from base of caudal, its base 2.1 to 2.5 in head; ventral 



