FISHES OF WEST COAST OF PERU. 9 



7. MUSTELUS NIGROMACULATUS. new species. 

 TOLLO. 



Plate 2, fig. 2. 



Two specimens, males, the type. Cat. No. 77699 U.S.N.M., 50 cm. in 

 length, and a paratype, 51 cm. in length (field Nos. 09527 and 09533), 

 from Lobos de Tierra. 



Following are the dimensions of the type and paratype : 



Type. 



Para- 

 type. 



Total length 



Distance from tip of snout to first gill slit 



Distance from tip of snout to eye 



Diameter of eye 



Length of spiracle 



Breadth of head 



Depth of head 



Interorbital 



Depth of body 



Distance from tip of enout to front of mouth 



Distance between nostrils 



Distance between angles of mouth 



Distance from tip of snout to base of dorsal fin (not including the 



fleshy ridge) 



Base of first dorsal 



Length of anterior margin of first dorsal (not including broad fleshy 



base) 



Distance from origin of first dorsal to origin second dorsal 



Base of second dorsal 



Length of anterior margin of second dorsal 



Distance from origin of second dorsal to base of caudal 



Length of upper caudal lobe 



Distance from insertion of lower caudal lobe to notch 



Distance from tip of snout to insertion of pectorals 



Length of anterior margin of pectorals 



Breadth of distal margin 



Distance from base of pectorals to base of ventrals 



Distance from base of ventrals to base of anal 



Base of anal 



Distance from insertion of anal to base of caudal 



mm. 

 500 

 93 

 42 

 13 

 4 

 58 

 34 

 27 

 67 

 29 



16.5 

 35 



160 

 64 



53 

 150 



55 



49 



96 



99 



75 

 106 



75 



68 

 130 



90 



30 



57 



mm. 

 510 



91 



42 



12 

 3.5 



56 



31 



25 



68 



29 



18 



35 



165 

 61 



48 

 162 



50 



39 



91 

 103 



80 

 102 



69 



53 

 130 



96 



30 



56 



Body robust, rather deep; snout blunt, thick, and fleshy; head 

 slightly depressed; mouth wider, more evenly rounded, and nearer 

 tip of snout than in the related species from Peru; teeth with a 

 central blunt or more or less pointed cusp, the majority of those in 

 upper jaw being provided with a lateral cusp posteriorly and a 

 shoulder toward the symphysis, having the general appearance of a 

 cusp worn away, those on the lower jaw approaching more nearly 

 the teeth of M. abbotti, the lateral cusps as a rule being less pro- 



