fh 
5O 
differences incidental to its stage. The above description 
should be compared with the apparently similar one in 
Sebastolobus (Starks, op. cit.), and with the very dissimilar 
one occurring in the herring.* 
If the last distinct vertebra (fig. 14, V.43, 19, V.42) 
be now examined, it will be seen that the neural spine 
(V.S.43, 42) resembles the haemal spine (H.S.30, 29) in 
structure, but that both are peculiar. Hach consists of a 
partly cartilaginous shaft behind and a thin laminate 
portion in front. ‘The posterior shafts so closely resemble 
the succeeding epural and hypural bones respectively as 
to suggest that an epural above and an hypural below have 
fused on to the laminate portions, which latter are un- 
doubtedly similar to and perhaps represent the neural and 
haemal spines in front. As, however, we have no positive 
evidence of such a fusion, the spines in question are here 
described as simple neural and haemal spines. 
Wedged in between U + Hp. 3 and W.S. 43 (fig. 14) 
are two partly cartilaginous spines (Hp. 1 and 2) which 
are closely connected by ligament with each other and 
with the last neural spine, but which are not sufficiently 
long proximally to reach the vertebral column. The 
gradual increase in length of these spines as the animal 
grows older suggests that they may in senile forms become 
connected with the vertebral column. That they develop 
in the same way as the neural spines seems certain, 
although there are no vertebr ostensibly belonging to 
them. One is appreciably larger than the other, and there 
is a big gap between the second and U. + Hp. 3. They 
represent the epural or epiural bones of other authors. 
The second hypural bone (Hp. 2) is of the same shape 
and structure as the upper piece (U + Hyp. 3), both being 
cartilaginous distally and strongly ossified proximally. 
* Duncan Matthews, Fishery Board, Scotland, Report v., 1886, 
