WOODWARD : FOSSIL FISHES OF THE UPPER LIAS OF WHITBY. 
39 
and direction of the small longitudinal furrows separating the orna- 
mental ridges on the various scales differ a good deal, as shown in 
the enlarged outline-drawing (fig. la) ; but they are most numerous 
at the anterior border of the scale, and most frequently reach the 
hinder border of the scales of the foremost rows, where the direction 
is comparatively oblique. The narrowed ventral scales" exhibit only 
two or three longitudinal ridges, while the deepest flank-scales have 
perhaps eight, in part fused together. The enlarged scales in the 
pelvic and anal regions are not shown ; but the arrangement of the 
diminutive scales at the base of the lower caudal lobe is interesting. 
The latter (shown enlarged in fig. Ih) are quite smooth, while those 
of the marginal row bordering the fin-rays are club-shaped, excessively 
elongated in the direction of these rays and pointed at the end. The 
" lateral line," as usual, is shown to be remarkably low on the flank, 
the course of the sensory canal being marked by large vertical clefts 
near the hinder end of a few scales of the series it traverses. 
Some further information as to the characters of the head may 
be obtained from two other specimens in the British Museum, num- 
bered P.858 a and 35581. The first (pi. v., fig. 2) exhibits the 
longitudinal ridges on the maxilla (mcc.) and the upturned ridges on 
the mandible (md.) ; while the ornament on the operculum (op.) and 
a fragment of the suboperculum (s.op.) is remarkably well shown. 
The two or three uppermost ridges on the operculum are horizontal ; 
then some short ridges are intercalated behind, and those below 
trend downwards but are less subdivided than in the original of fig. 1. 
The ridges on the suboperculum are chiefly horizontal, and the true 
form of this bone is indicated by an impression in No. 35581, which 
enables us to add the sharp outlines to our figure. Below the sub- 
operculum and mandible there are obscure remains of the smooth 
branchiostegal rays and gular plate (gii.), which are only finely 
punctate. An impression of one of the ceratohyal bones in a third 
specimen (fig. 3, ch.) presents no noteworthy feature. 
The last specimen is the ventral aspect of a small fish exposed 
in a nodule (Brit. Mus., No. P.5222), and is especially interesting 
as exhibiting the paired fins and squamation. The pectoral fin on 
the left side (pet.) has at least twenty-two stout rays, with finer rays 
