394 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



with three to five rather obscure dark spots on middle of side under 

 posterior rays of dorsal; head with dark marking, these more numerous 

 in the largest specimens than in the smallest ones; dorsal and ventral 

 unpigmented; caudal unpigmented, except for a dark vertical line on 

 its base; anal plain, except for a black spot with a backward exten- 

 sion at the base of each ray; lower half of pectoral in the larger speci- 

 mens, and nearly the entire fin in the smallest ones, black. 



The description is based on 10 juveniles, 8 to 21 mm. (6 to 18 mm. 

 to base of caudal) long, taken by the Mission. Eight specimens were 

 caught in a surface net off Sechura Bay, at latitude 5°52'30" S. ; . 

 longitude 81°28'30" W., and two under a light at Mazorka Island in 1 

 the Huaura group. These specimens all retain some of the juvenile 

 characters, such as the prominent bony ridges over the eyes; the 

 juvenile color markings consist of the conspicuous black pectoral fins 

 and the prominent series of dark dots along the base of the anal, 

 while general pigmentation is lacking, 



I am unable to identify these juveniles with any known species, 

 and I defer giving them a name, because of the pronounced changes | 

 which are known to take place during development in at least some * 

 of the blennies. The fins are well enough developed, except for the 

 spinous part of the dorsal in the three smallest specimens, to permit 

 an accurate enumeration of the rays. However, it is not possible to 

 definitely distinguish these specimens from the known species on the 

 basis of the number of fin rays alone. The specimens seem to be near 

 the form herein described as H. robustus. Although the soft rays in 

 the dorsal apparently are rather fewer, they overlap in one specimen. 

 Furthermore, the collections contain one specimen of robustus, only 

 19 mm. (16 mm. to base of caudal) long, in which the bony ridges 

 over the eyes, if it ever had them, have disappeared, and the inter- 

 orbital instead of being broad and flat is narrow and concave. How- 

 ever, it does retain three spines on the margin of the preopercle. If 

 the differences in the structures of the interorbital are of no specific 

 value, it must be assumed that development progresses very unequally 

 among individuals of the same species. The material now at hand 

 does not seem to justify any definite conclusion. 



Range. — Coast of Peru. 



Family CLINIDAE 



Body oblong or elongate; premaxillaries generally more or less 

 protractile; teeth in the jaws in an outer principal series, followed 

 anteriorly by a band of small pointed teeth; teeth often present on 

 vomer and palatines; gill membranes united and free from the isthmus; 

 scales usually, though not always, present; spinous part of dorsal 



