﻿ELONICHTHYS SEMISTRIATUS. 



51 



hollow, their slender tubular cavities having been, in the recent state, occupied by 

 cartilage. 



The scales seem to have been rather small for the size of the Fish, and they are best 

 seen on some of the more fragmentary specimens. As in the other species of the genus, 

 they are remarkable for the small amount of anterior non-ganoid-covered margin. The 

 largest scales on the flank near the front measure rather more than ^ inch in height 

 by rather less in breadth, and are thus nearly equilateral ; the upper edge is concave, the 

 lower convex ; and from near the middle of the upper one a moderately sized articular 

 spine projects. The articular spine disappears in the scales of the caudal region, which 

 are also smaller ; those of the belly are much less high than on the flank, and have their 

 covered anterior margin more developed ; the anterior superior angle being also consider- 

 ably produced, upwards and forwards. The ornament of the exposed surface of the scales 

 (PI. IV, fig. 3) is characteristic. From the anterior and also from the upper margin a 

 number of well-marked ridges with intervening furrows proceed obliquely downwards and 

 backwards, sometimes simple, sometimes bifurcating or joining with others, sometimes 

 multiplied by intercalation. They do not, however, proceed to their apparent desti- 

 nations on the posterior and inferior margins, but soon stop short, the rest of the area of 

 the scale being occupied by numerous well-marked, or coarse, punctures. In the most 

 anteriorly placed scales (PI. IV, fig. 2) the pattern seems slightly different, the ridges being 

 more pronounced ; and posteriorly and inferiorly an appearance is caused as if they blended 

 together to form a network, the meshes of which correspond with, and are in fact the 

 forerunners of the punctures characteristic of the scales behind them. Specimens from 

 which the external ganoine layer has flaked off show the corresponding ridges on the bone 

 below, passing in a wavy oblique anastomosing course right over the whole surface. 



On specimens 2 and 3 portions of the head are seen, though much crushed and 

 obscured. However, the hinder part of the gape is clearly enough seen, both jaws being 

 armed with powerful teeth of several sizes. The larger teeth, which are pretty close 

 together, four of them being seen in the lower jaw of No. 2 in the space of f inch, are 



inch long, and inch in diameter at the base, and are somewhat irregularly inter- 

 spersed with smaller ones, from two thirds to one half their size, some of these being in 

 the same row with the larger teeth, others outside them. All the teeth are slender- 

 conical in shape, sharp, smooth, and pretty strongly curved inwards towards their apices 

 (PI. Ill, fig. 11). 



Specimen No. 10 presents a view of the head both from below (PI. Ill, fig. 9) and 

 from the left side (PI. Ill, fig. 10); unfortunately it is not in very good preservation. 

 The lateral view, a little distorted by the crushing to which the specimen has been sub- 

 jected, displays two of the opercular bones, a portion of the maxilla, and the hindermost 

 of the branch iostegal rays. The operculum is an oblong plate, 1^ inch long by 

 -f inch broad, with acute antero-superior and postero-inferior angles, the other two angles 

 being correspondingly obtuse. Below it is placed the interoperculum, quadrate in 



