474 J. FRANK DANIEL 
which extends over two and one-half vertebrae (17—183) in the 
female; (15-18) in the male. From the top of this plate arise 
two other cartilages, the anterior of which is twice the width 
of the posterior. From the former there appear four rows of 
radiating pieces, each row of which contains three cartilages. 
Capping the second and third rows is an extra cartilage and 
over the fourth is a similar cap of a double piece. 
2. Second dorsal fin (fig. 25). The second dorsal fin, like the 
first, is provided with a basal piece (b.c.) one-half the height 
of the spine; it extends over three (46-48) diplospondylous ver- 
tebrae in the female; (44-48) in male. From it arise three 
radials which point in a more posterior direction. The most 
anterior of these is the smallest. Passing from it is a double 
row of two segments capped with a broader piece. The second 
radial, though a single piece proximally, is bifid distally. From 
the distal end arise two rows of three cartilages each. The third 
radial is a truncate cone which rests on its apex. Upon its base 
it supports in an irregular fashion six cartilaginous pieces. — 
3. The caudal fin (fig. 17). The ventral rays of the caudal 
fin or tail, as we have seen are an integral part of the axial skele- 
ton, being the prolonged haemal spines. These consist of a 
series of forty rays, each of which corresponds to a vertebra. 
Beyond the tip of these, in the adult is an undifferentiated 
(fused) mass. In this region interdorsal pieces are present as far 
back as the ninety-fourth to the ninety-seventh vertebrae, while 
interventral pieces extend back to the ninety-ninth vertebra. 
The dorsal lobe of the fin is supported by rays which unlike those 
supporting the ventral lobe, are not equal in number to the cen- 
tra, forty-six being present inone specimen examined. The first of 
the dorsal rays is small and the second arises as a broad clear 
piece of cartilage over the seventieth or seventy-first vertebra. 
Back of this the rays are numerous and are more or less regular 
to the ninety-fifth vertebra. At the tip of the tail they fuse 
into a common mass (fig. 17). 
In the caudal region alternate basidorsals are perforate. back 
to the ninety-fifth vertebra, with the exception of the eighty- . 
ninth and ninety-third. The eighty-ninth although perforate 
