1909.J K.- E. Eloyd : Deep-Sea Fish caught by the “ Investigator.” 165 
borders, if prolonged, would meet in front at an angle of 40°. The preorbital pro- 
cesses therefore appear to converge. The length of each labial tentacle is equal to 
the width of the mouth. 
The osseous plates between the ventral fins are unusually thick. The greatest 
length of each anterior ventral plate is equal to the greatest breadth of both com- 
bined. The greatest length of the posterior ventral plates is half that of the anterior 
ones. The greatest length, in both cases, is to one side of the middle line. A quad- 
rangular portion of the posterior plates fits into a corresponding hiatus in the anterior 
plates. Throughout the length of the body, on either side, there are four rows of 
plates, each with a large spine shaped somewhat like a rose-thorn, their points curv- 
ing backwards. The lowest row is much less conspicuous than the others. 
There are large postorbital, occipital, post- temporal, and two opercular spines, a 
small upper and a large lower one, on either side. There is one small median spine, 
an orbit’s length in front of the orbits. 
The greatest height is one-fifth the total length. Total length of the single speci- 
men 6^ inches ; greatest length of the head 3 inches. 
Colour. — Reddish yellow, pectorals grey, dorsals tipped with black. 
Habitat. — Gulf of Aden, 130 fathoms, Station 360. Registered No. 
Division JUGUEARES. 
Family ZOARCIDÆ:. 
Diplacanthopoma squamiceps , Eloyd. 
Rec. Ind. Mus., vol. i, part i, p. 10 (1907); Illusir. Zool. “ Investigator Fishes, 
pi. xlii, fig. (1908). 
Corresponds with the generic definition in the following respects : — the form and 
arrangement of the fins, of the teeth and the gills, in the number of the branchioste- 
gals (8), in the absence of pseudobranchiæ and pyloric cæca, in the obscurity of the 
lateral line, and in the presence of radiating spines on the opercles. It differs from 
all known species in this important respect : — there are scales on the head as far for- 
ward as the posterior limit of the eyes and on the opercles and sides of the head as 
far forward as a line dropped vertically from the posterior border of the eyes. The 
head is much depressed and the eyes are close together and look upwards to a great 
extent, being separated by less than their diameter ; this gives the head a very different 
appearance from that of the other three known Indian species of the genus, in all of 
which the eyes are separated by about if times their diameter. 
There are deep mucus pits on the head and in a semicircle below the orbits. 
There are no pseudobranchiæ, but in the position of these organs there are two 
very short and slender filaments which are vestiges of this organ. I find that the 
type specimens of D. riversandersoni and D. rani ceps have precisely similar vestiges. 
This seems to be a strong argument for including this new species under the genus 
Diplacanthopoma. 
