378 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [90] 
institute a comparison with the corresponding stage in Histiophorus. 1 
shall confine myself to a brief mention of the smaller and a little more 
extended one of the largest of these youthful examples. This is unfor- 
tunately somewhat obscured by the stomach juices, and on this account 
is not fit to be made the subject of an illustration, which is so much the 
more unlucky since there exists no representation of a young Sword-fish 
at just this stage of development. It has a much slenderer form; the 
height is only 10 millimeters, and is contained 19 times in the total 
length; the length of the head (from the tip of the upper jaw to the 
gill-opening) is 68 millimeters, over one-third of the total; the “ bill” 
itself (from the tip of the upper jaw to the anterior margin of the socket 
of the eye) is more than 3 times as long (52 millimeters) as the distance 
from the anterior margin of the socket to the gill-opening; the lower 
jaw is only 12 millimeters shorter than the upper jaw; measured to the 
angle of the jaw it is, however, only 4 millimeters shorter (48 millimeters) 
than the length when taken to the anterior margin of the socket. The 
upper jaw is arched above, flat below, nearly as in Tetrapturus, twice 
as wide as high (in the same place), and its form is very different from 
what it is later. The caudal is not deeply forked; the height of the 
dorsal appears to have been nearly double that of the body; the pec- 
toral is comparatively short (21 millimeters); no trace of ventrals is 
seen; the caudal keel is likewise invisible (see below); the skin is 
everywhere covered with pointed scales or shield-like plates, which he 
side by side, not imbricated; among which may be distinguished larger 
and smaller ones.* Of the larger a series extends parallel with the dor- 
sal outline on each side of the dorsal fin from the head to the root of the 
tail, and close below each of these series is a similar one formed of some- 
what smaller plates; also parallel with the ventral outline on each side 
of the anal fin extends such a series of larger plates, accompanied above 
at some distance by a somewhat smaller one; but in front of the anal, 
towards the under part of the belly, these two series of larger plates dis- 
appear gradually in the common covering of pointed, small scales, which 
here on the belly are larger than up towards the back; on the whole 
hind part of the body and tail is seen, on the contrary, quite plainly its 
four regular series of larger skin-tubercles, separate, along tbe sides of 
the fish, with a comparatively small belt of little scales. Its larger 
shields are strongly compressed, keeled and ribbed, so that the ribs 
radiate from the keel backwards and downwards towards the basal mar- 
gin of the shield; from each keel project three to six sharp, curved 
points, directed backward, of different sizes, the smallest of each group 
in front, the largest behind. The small scales, furnished in a similar 
manner with little points, extend out over the whole head and bill, as 
well as the upper and under jaw. The margin of the upper jaw is 
*The small scales repeated in Tetrapturus as a fine layer of diminutive roughnesses 
outside the bony scales, especially characteristic of this genus and the Histiophori 
(which likewise occur in Thynnidw), are not homologous with these. 
