51 
It articulates as shown in fig. 14 with U + Hp. 3 above 
and in front, the latter articulation making the two ex- 
panded tail bones unequal. The first ostensible hypural 
(Hp. 1) is a wedge-shaped bone of the same structure as 
the 2nd, but much smaller. It is closely attached by liga- 
ment to the last haemal spine, but proximally does not 
reach the vertebral column. 
Each bone in the tail giving articulation to fin rays 
bears a thin terminal cartilaginous epiphysis (ep. fig. 14). 
As in the other fins there is a pad of sub-cartilaginous 
tissue intercalated between the bones of the vertebral 
column and the proximal ends of the fin rays. This, as 
before, is embraced by the diverging halves of the rays 
(F.R.). The number of the latter in the caudal fin varied 
in the specimens examined around 20—sometimes more 
and sometimes less. What possibly may be regarded as 
the typical condition both as regards number and places 
of articulation is represented as follows (ep. fig. 14):— 
Shaft of last neural spine, 1; Epural 1, 1; Epural 2, 2; 
Hypural 3, 6; Hypural 2,6; Hypural 1, 3; shaft of last 
haemal spine, 1; total, 20. 
Each fin ray is of the same structure as those of the 
pectoral and pelvic fins, with the exception that there are 
no articular processes connecting the individual rays with 
their neighbours, each ray in the caudal fin, therefore, 
being independent of those immediately above and below 
it. With the exception of about the three most dorsal 
and ventral, each ray bifurcates distally, but does not split 
up further to form a brush as happens in the caudal fin 
rays of the Sole according to Cunningham. 
9.—Dorsat Fin (Figs. 17 and 19). 
The dorsal fin commences very far forwards in the 
pseudo-medial line, and in the specimen on which the 
