FISHES OF HAWAIIAN ISLANDS. 
641 
included in the membrane and are equal in height, their length half that of head; a few of the poste- 
rior rays are shortened; last dorsal and last anal rays are cleft to the base; except the modified pectoral 
rays and a few at base of caudal lobes, all rays are forked, those of the anal fin near extreme tip only; 
in males of II. langsdorfii, there are no filamentous or free rays; the spinous dorsal has a convex out- 
line, and some of the middle rays of the soft dorsal are the highest in the fin; anal rays not specially 
produced in males of either species; in II. citrinus, the caudal is truncate or slightly concave, this being 
more marked in males, where the lower caudal rays are a little longer than the upper. In langsdorfii, 
the caudal is convexly rounded in both sexes; the lower 3 (or rarely 4) pectoral rays are simple, thick- 
ened and longer than the rays immediately above them; they are largely free, being joined to one 
another and to the rest of the fin by a very low membrane at extreme base. They resemble strikingly 
the free pectoral rays of Trigla. The ventral fins are sub jugular in position, their insertion being in 
advance of pectorals; they contain 5 branched rays in addition to the spine, the inner ray the longest, 
the others progressively shortened. Cuvier and Valenciennes have erroneously figured the ventrals 
as rounded in H. langsdorfii. 
The fin rays are very constant in this species. We have found but 2 variations from the normal 
formula, the dorsal spines numbering but 5 in one specimen, the free pectoral rays increased to 4 on 
one side of another specimen. 
The body is naked, with the exception of the series of lateral plates, which agree in structure and 
in number with those of H. langsdorfii. These plates are placed obliquely antero-posteriorly, the 
anterior upper portion nearly horizontal, its surface roughened by from 2 to 5 minutely denticulated 
ridges, the lower posterior part vertical and smooth. At the angle each of these plates is provided with 
a very strong spine directed backward. In this species and in langsdorfii a minute concealed spinous 
point can be detected below and behind the strong spine, but in no specimen have we seen the pair of 
equally strong spines figured by both Cuvier and Valenciennes and by Temminck and Schlegel, as 
characteristic of langsdorfii. The pores of the lateral line occur below the spinous crest in the soft 
intervals between the vertical laminae. The plates are always 27 in number in both species. 
Color in life very bright lemon-yellow or olive-yellow on all upper parts, including fins, white or 
silvery below, the boundary between the 2 colors coarsely freckled with brown spots, which cover 
also more or less of the back; faint traces of 4 dark cross-bars on back, seldom evident except in the 
young; soft dorsal translucent, with many round yellowish green spots; a basal series larger than the 
others, with each spot nearly half as large as pupil ; a large black blotch at base of posterior dorsal spines; 
anal fin with a terminal orange band, but without black margin ; upper margin of spinous dorsal orange; 
caudal with some orange, its base and terminal portion dusky. In one very young specimen, 95 mm. 
long, there is a broad black bar through the middle of the spinous dorsal; five dusky cross-bars are 
evident: 3 wide bars opposite spinous dorsal, middle of soft dorsal and end of soft dorsal, respectively, 
and 2 narrow bands, intermediate in position between the wide bars; there is also a very narrow sub- 
terminal dark line on the anal fin, similar to but fainter than that characteristic of adult specimens of 
langsdorfii. In no other specimen of citrinus is there a trace of the anal band. 
In the stomach of one specimen were found remains of crabs and fishes. The specimens of H. 
langsdorfii with which we have compared citrinus were dredged by the Albatross May 11, 1900, at 
station 3717, off Hondo Island, Japan, at a depth of 75 to 100 fathoms. A specimen of the same 
species is at hand from Kagoshima. These differ somewhat from current descriptions and figures of 
langsdorfii, but probably belong to that species. 
Specimens were taken at the following stations during the Hawaiian investigations: Nos. 3858, 
Pailolo Channel, 128 to 138 fathoms; 3859, Pailolo Channel, 138 to 140 fathoms; 3957, near Laysan 
Island, 173 to 220 fathoms; 3965, near Laysan Island, 116 to 147 fathoms; 4079, off the northeast coast 
of Maui, 143 to 178 fathoms; 4080, off the northeast coast of Maui, 178 to 202 fathoms; 4081, off the 
northeast coast of Maui, 202 to 220 fathoms; 4103, Pailolo Channel, 132 to 141 fathoms; 4114, off the 
northwest coast of Oahu, 154 to 195 fathoms; 4120, off the northwest coast of Oahu, 167 to 216 fathoms. 
