THE SHORE FISHES OF PERU 409 



advance of mouth, entering dorsal profile; both lips fringed, those of 

 lower lip much the larger ; maxillary extending to vertical from anterior 

 margin of pupil, 4.0 in head; teeth very small, pointed, in a narrow 

 band anteriorly in each jaw; margin of preopercle free, broadly convex; 

 opercle above with rather large cutaneous tentacles, the margin below 

 the tentacles straight; gill rakers undeveloped; lateral line complete, 

 high and arched on first 12 scales, then abruptly decurved to middle 

 of side; scales rather large, thin, with smooth membranous borders, 

 4 rows between anterior part of straight portion of lateral line and 

 base of dorsal; dorsal and anal of equal length, the origin of each fully 

 the length of snout and eye behind margin of opercle, also approx- 

 imately coterminal; caudal well separated from dorsal and anal, with 

 a nearly straight margin, about as long as postorbital part of head; 

 ventrals close together, inserted at vertical from preopercular margin, 

 3.3 in head; pectoral moderately long, reaching base of seventh ray 

 of anal, about as long as head, 5.2 in length. 



Color gray; back with a row of dark spots, one on each side of every 

 ray, extending slightly on fin; a pale streak next to the dark spots on 



Figure 80. — Myxodagnus macrognathus, new species. From the type, 70 mm. long, Lobos 

 de Tierra Bay, Peru (U.S.N.M. No. 128224). 



back, occupying roughly a row of scales; followed below by two rows 

 of scales with dusky margins; then another pale streak on the next 

 row of scales; straight part of lateral line in a dusky stripe; lower part 

 of side slightly dusky; upper surface of head and nape with many 

 irregular dark markings of unequal size, extending forward on snout 

 and dorsal surface of lower jaw; dorsal fin plain, except for the dark 

 spots on base already mentioned; caudal pale, with suggestions of 

 two dusky cross bars; anal pale, with dusky spots at base, extending 

 as dusky punctulations on fin, especially posteriorly; ventral pale; 

 pectoral pale, with indefinite dusky markings on upper half. 



A single specimen (U.S.N.M. No. 128224) 70 mm. (60 mm. to base 

 of caudal) long, is included in the Peruvian collections. This example, 

 which was seined in Lobos de Tierra Bay by the Mission, must serve 

 as the type of a new species. It was compared with specimens of 

 M. opercularis Gill from Baja California. The principal differences 

 are: The fewer dorsal rays in opercularis, 36 including simple and 

 articulated rays in six specimens and 37 in one; the longer pectoral 

 fin, though variable is contained 2.8 to 4.25 in length; the absence of 



