THE SHORE FISHES OF PERU 35 



deep, its depth 5.4 to 5.7 in head to first gill slit; head much broader 

 than deep, its depth over middle of eyes equal to or a little greater 

 than width of mouth, its length to first gill slit 3.9 to 4.1 in length 

 anterior to base of upper lobe of caudal; snout somewhat pointed, 

 2.2 to 2.4 in head, its preoral length equal to or a little greater than 

 width of mouth, 3.0 to 3.4 in head; eye elongate, 7.6 to 8.7; spiracle 

 elongate, about as long as pupil; mouth much wider than long, its 

 width a little less than distance between outer margins of nostrils, 2.8 

 to 3.2 in head; labial folds present, the upper one longer and broader 

 than the lower, the latter reaching about halfway to symphysis; 

 teeth anteriorly symmetrical, with one central cusp, those at sides 

 asymmetrical with a small cusp posteriorly; dermal denticles variable, 

 with rounded base and sharply pointed apex, occasionally with a 

 notched margin, some with one or two low ridges if any at base, occa- 

 sionally with a broad median ridge extending to apex; first dorsal 

 originating about over beginning of distal thii'd of upper margin of 

 pectoral, greatest height of fin (without fleshy base) somewhat ex- 

 ceeding space between eyes, with slightly produced posterior lobe, 

 its distal margin somewhat concave; predorsal length 2.25 to 2.45 in 

 length anterior to base of upper lobe of caudal; distance between 

 dorsal fins 3.7 to 4.2; second dorsal similar to first, though smaller, 

 its origin well behind vertical from tip of distal margin of ventral; 

 upper lobe of caudal with a nearly straight and oblique distal margin, 

 entire length of lobe 3.5 to 3.9 in length of body anterior to its base; 

 lower lobe separated by a notch, with long concave margin notably 

 exceeding length of snout and eye; anal small, its origin about under 

 middle of second dorsal, with rather strongly exserted posterior lobe, 

 base of fin 3.0 to 3.4 in head; ventral inserted well behind base of 

 first dorsal, with straight to somewhat concave distal margin, outer 

 margin 1.9 to 2.3 in head; pectoral notably larger than ventral, 

 generally with slightly concave distal margin, inserted a little behind 

 third gill slit, its greatest length 5.0 to 6.2 in length anterior to base 

 of upper lobe of caudal. 



Color of small preserved specimens varying from pale gray to 

 dark gray; back and sides with irregular black spots and specks, 

 some individuals profusely spotted, others with comparatively few 

 spots, one specimen with not more than a dozen specks on anterior 

 part of body and more posteriorly; fins pale to dusky, black spots 

 sometimes extending somewhat on bases of dorsal fins. The black 

 spots, sometimes at least, seem to be lost with age, as Mr. Lobell of 

 the Mission remarked in his field notes that 14 black-spotted embryos, 

 of which 3 were preserved, were removed from a "plain dark gray 

 female." 



The description is based on the three embryos just mentioned, 

 respectively 370, 390, and 396 mm. long, and six other specimens 

 372 to 490 mm. long. The type of Mustelus nigromaculatus Ever- 



