1910 Bulletin ^7, United States National Museum. 



head with minute spiny scales, most abundant on the upper half; all of the 

 back above lateral line densely covered with small spiny scales; lateral 

 line made uji of raised tubes ; a few rough scales under lateral line on 

 second half of body; l)ranchiostegal nicml)ranes broadly imited and well 

 freed fnmi isthmus; slit behiud fourth gill obsolete; spinous dorsal very 

 high, its longest spine f as long as head; about 4 large, dark blotches 

 across back and several smaller ones between them. Length 3J inches. 

 Bering Sea, off Trinity Islands, in deep water. (Bean.) 



Concerning this species, Dr. Gilbert observes: 



This species is distinguished from all others iu the genus Trelus by the 

 absence of the series of enlarged spinous plates along the base of the dorsal 

 tin. Our specimens agree with tlie type in having the sides above lateral 

 line densely covered with scales. These are not uniform in size, and are 

 arranged in rather irregular oblique series. The sides behind pectorals 

 contain large spinous plates, and the tail below lateral line is densely 

 scaled, leaving only a narrow, naked strip along each side of anal base. 

 As stated, the upper half of head is densely covered with small prickles. 

 As ia other species of Icvlus, tiie upper pi-eopercular spine may bo simple 

 or bifurcate. The latter condition obtains in most of our specimens. All 

 of the preopercular spines are weaker than in, other species of the genus. 

 Compared with the nearest allies, Icdus exirrops and Icelus canaliculattis, 

 the species is further distinguished by its more robust body (the depth 

 approximately 5 in length, instead of nearly 6), by the smaller eye (in 

 which the snout is contained li times instead of nearly twice), the nar- 

 rower interorbital space, the very slight developnu^nt of the occipital 

 crests, tbc obsolescense of the occipital spines, and the great height of the 

 spinous dorsal fin in the male specimens. It has also a shorter second 

 dorsal fin, the formuhcin 11 specimens being IX, 19; IX, 19; IX, 19; IX, 19; 

 IX, 19 ; IX, 20 ; X, 19 ; X, 19 ; X, 20 ; X, 20 ; X, 20. It has less the appearance 

 of a deep-water species, the mucous canals and pores being less conspicuous 

 and the color lighter, with no brownish-black or blue-black tints. In alco- 

 liolic specimens the upper parts are light brown, the lower side of head and 

 belly, including the ventral fins, whitish. A vertical black bar occupies 

 base of upper half of pectorals, a streak extending from its lower end out 

 along middle ray of fin. The Idack bars characteristic of its congeners 

 are here represented by irregular, rather sharply defined, blotches on back 

 and sides. These extend also onto spinous and soft dorsal fins. A distinct 

 dark streak runs forward from eye, crossing premaxillaries, and leaving 

 tip of snout pale. Mouth and gill cavities white. North Pacific; numer- 

 ous specimens taken by the Alhati-osn south of the Alaskan Peninsula, at a 

 depth of 138 fathoms. (Gilbert.) (scit/«m, shield; <7eT0, I bear.) 



Icelus scutiijer. Bean', Proc. U. S. Nat. Mus. 1890, 41, Trinity Islands, Alaska, 56° N., 154° 

 20' W., at Albatross Station 2853, in 159 fathoms; Gilbeet, Kept. U. S. Fish Comm. 

 1893 (1896), 415. 



