38 RAMSAY H. TRAQUAIR’S 
surface is central and sharply defined. The scale markings are peculiar and 
characteristic. Along the sides of the body, as far as the tail pedicle, the 
exposed surface of the scale is ornamented by somewhat coarse and closely 
placed ridges, which, commencing at the upper margin, descend in such a way 
as to form one median ridge, surrounded by several others, which running 
parallel with each other, and with the anterior and posterior margins, join 
each other below round the lower extremity of the median one; or—to put the 
matter in another way—we have a set of concentric ridges parallel with the 
anterior, inferior, and posterior margins, with an odd one in the middle, or 
sometimes with two uniting in a loop; in addition, there are often one or two 
fine vertical striz along the anterior margin. A somewhat different pattern is 
observable along the back (fig 18), extending downwards to, and including the 
second longitudinal row of scales above the lateralline. Here there is ordinarily 
only one marginal ridge, running closely along the anterior, inferior, and posterior 
margins, within which the area is, according to the size of the scale, occupied 
by from two to five diagonal and parallel ridges, passing from before down- 
wards and backwards. The caudal body prolongation is comparatively weak 
and narrow; its minute lozenge-shaped scales are ornamented by diagonal 
ridges only ; striee of a similar description characterising also the large V-shaped 
scales which run along its upper margin. 
The pectoral fin is small, its length being hardly more than half that of the 
head ; it is acuminate in shape, and consists of about twelve rays, of which the 
principal ones are unarticulated till towards their terminations. The ventrals 
are in no specimen well preserved, but seem to have been likewise small, and 
with their rays somewhat distantly articulated. The median fins are, on the 
contrary, of tolerably large size. The dorsal is situated far back, and is 
triangular-acuminate in shape; its rays, the number of which cannot be accu- 
rately ascertained, are slender, smooth, and distantly articulated. The anal 
may be said to be placed opposite the dorsal, though in some specimens it 
seems to commence slightly in front of it, and to be also somewhat larger ; it 
is sharply acuminate in front, with concavely excavated posterior margin ; the 
rays are of the same character as those of the dorsal. The caudal is well 
developed, deeply cleft, and inequilobate ; its rays resemble those of the other 
median fins. 
Remarks.—This is one of the most beautiful of the many beautiful fishes 
which the Eskdale strata have yielded, and nothing can be more strikingly new 
than its specific characters, of which the first which arrests the attention is 
the unusually bold sculpture of the scales, together with the peculiar form of 
those on the anterior part of the flank. Of hitherto described species, the only 
one which bears any resemblance to it is the Cycloptychius carbonarius of 
Huxley, the points of likeness being—the slender elongated form of the body, 
