AND MESOZOIC FISHES. 
437 
Traquair). The operciila are very large, and in this specimen they are shoved up- 
ward so as to overlap at the median line. Their length enters the total length of 
the sknll three and a half times, and is a little greater than that of the parietal 
bones. Their superior margin is beveled off from a low longitudinal thickening 
from wdiich some low wrinkles radiate downward. Enamel is jrresent on the supe- 
rior surface of the skull, on the border of the frontal bone posterior to the orbit, and 
on the anterior part of the postfrontal bone. There are grains of enamel scattered 
on the parietals. On the supratemporals there are closely placed, concentric, inter- 
rupted lines on the superior part, and irregular patches of larger size on the inferior 
part. There are large patches of enamel on the opercnla. The superior bones of 
the skull are everywhere roughened with minute tuberosities, which fuse into 
transverse ridges on each side of the sagittal suture. The maxillary bones are dis- 
played partly on the superior, partly on the inferior faces of the specimen. They 
are rather slender, and their distal extremities are broken ofi’. 
There is a short pyriform s^nnphyseal, entirely closed by the mandibular rami, 
and a median gular bone wdiich joins the gularswith a concave suture. Tlie gulars 
are large, and measui'e three times as long as wide at the middle. They are cut off 
obliquely on the inner side, posteriorly, by the chevron-sha])ed arrangement of the 
pectoral scales. Several large external gulars. The posterior e.xtremities of tlie 
mandibles are bi’oken so that their proportions cannot be exactly ascertained, hut 
the length preserved is six times the width o^iposite the anterior gular. The sur- 
face of their inferior portions is marked by coarse impressed punctures besides 
the usual minute ones. The former are not present on any other part of the fish 
The scales are large ; between the bases of the iiectoral and ventral fins can lx? 
counted about twenty-one rows, and between the ventral and the first dorsal imme- 
diately above, eight rows. The first dorsal fin is above the ventral, and the second 
dorsal above the anal. Thex'e are two large scales on each side wdiich embrace the 
base of the first ray of the first dorsal and anal ; the other fins are too imperfect at 
the base for description. The caudal fin is shortly heterocercal, and there are six 
broad fulcral scales projecting from the side of its inferior border. In all the fins the 
rays are segmented. A half dozen rays near the border are coar.se, but the remain- 
ing rays are finer. In all the fins the coarse rays are distally subdivided. 
Measitremexts. 
MM. 
Total length of specimen (20 mm. intercalated behind head) . . 9o0 
Length to anterior border of orbits . . . 40 
Length to posterior border of parietals . . . . .143 
Length to posterior border of oixerculum ... ... 230 
Length to anterior base first dorsal fin . ... ... 020 
Width between orbits ... . ... ... 33 
Width of parietals and jTOstfrontals anteidorly . . . ... 38 
Width of parietals and pterotics posteriorly . . . . . .75 
