34 RAMSAY H. TRAQUAIR’S 
therefore peculiarly short and straight, and wanting in the usual more or less 
fusiform outline, while the tail pedicle is of great proportional depth. 
All that can be said of the head is that it is typically paleoniscoid in 
structure, with oblique suspensorium, &c., and that some traces of a minute 
ridged ornament are seen on some of its delicate bones, ¢.g., the mandible. The 
body-scales (fig. 11) are of moderate dimensions in proportion to the size of the 
fish, and are marked each with three or four delicate, yet sharply-defined and 
somewhat distant ridges, which run right across from before backwards, parallel 
with the superior and inferior margins ; on the minute lozenge-shaped scales of 
the caudal body-prolongation these ridges, now excessively fine, are diagonal in 
position ; the V-scales of the tail are proportionally largely developed. 
The pectoral and ventral fins are small, the dorsal and anal nearly opposite, 
though the former arises a little in advance of the latter. The two last named 
fins resemble each other in their triangular-acuminate contour; the caudal is 
not completely preserved, but its appearance seems to indicate that it was 
bifurcated in the usual manner. The fins are preserved only in the smaller of 
the two specimens, and their rays are so excessively delicate that it is im- 
possible to describe their articulations, but they are closely set, and appear to 
bifurcate towards their extremities. 
Remarks.—On account of its general structure, so far as can be made out, 
along with the form and position of the fins, this strange little fish is referable, at 
least provisionally, to the genus Rhadinichthys. Its prominent specific characters 
are its large head, short straight body, deep tail pedicle, and the scale sculpture 
consisting of a few delicate, straight, non-bifurcating longitudinal ridges. The 
scale ornament of Rhadinichthys Grossarti, Traq.,* another very small species 
from the Coal Measures of Lanarkshire, also consists of straight ridges, but 
these are more or less oblique in their direction, besides being closer and more 
numerous, while the shape of the fish, with its narrow elongated tail pedicle, 
forms a character at once distinguishing it from the form before us. 
Position and Locality—Near Glencartholm, Eskdale, in the Cementstone 
group of the Calciferous Sandstone series. 
Rhadinichthys (?) fusiformis, sp. nov. Traquair. 
Pl. III. figs. 1-5. 
Description—Length of an entire specimen, 63 inches; shape elegantly 
fusiform ; length of the head equal to the greatest depth of the body between 
the shoulder and dorsal fin, and contained 43 times in the total, 34 times up 
to the bifurcation of the caudal fin. The dorsal fin is placed far back, so as to 
be nearly opposite the anal; the caudal is very heterocercal and inequilobate, 
* Proc. Roy. Phys. Soc. Edin. vol. iv. pt. 3, 1878, pp. 237-245. 
