Elongate Perciform Fishes— Gosline 
95 
that interdigitate little if at all between the 
tips of the neural spines, and there is a rough 
but inexact correspondence between soft dorsal 
(and anal) rays and vertebrae. 
CAUDAL FIN: The tails of the ammodytoids 
are somewhat forked, those of the other fishes 
under investigation more or less rounded. In 
all, there is a reduction in the caudal ray num- 
ber from the typical percoid count of 17 prin- 
cipal rays, 15 branched. In Parapercis there are 
15 branched rays, but no outer principal un- 
branched rays. In Ammodytes and Bleekeria, 
there are 15 principal rays, 13 branched. In 
Hypoptychus, there are 13 principal rays; ap- 
parently 11 of these were branched, but since 
the fin rays of the available specimen are broken 
the branched ray count cannot be definitely 
established (the same is true of the dorsal, 
anal, and pectoral fins). Tripterygion and Crys- 
tallodytes have 10 principal rays, 8 branched. 
With regard to the caudal skeleton, Paraper- 
cis (Fig. 6a) is quite typically percoid (Gos- 
line, 1961). There are six separate hypurals, 
one uroneural, and three epurals; none of these 
elements are fused to the urostyle. In the caudal 
skeleton of the other five fishes, considerably 
more fusion and/ or reduction has occurred. Hy- 
purals 4 and 5 are always fused with the urostyle, 
and, in Crystallodytes (Gosline, 1955: fig. 7d) 
and Hypoptychus (Fig. 6d ), two or three of the 
lower hypurals as well. ( Fig. 6d must be viewed 
with some reservation, as the specimen from 
which it was drawn may have been aberrant 
in having the last two vertebrae fused.) There 
are two epurals in Tripterygion (Fig. 6b) and 
the three ammodytoids, and only one in Crys- 
tallodytes. 
PECTORAL FIN: The total number of pec- 
toral rays in the fishes investigated is 15 in 
Tripterygion and Parapercis, 13 in Ammodytes 
and Bleekeria, 12 in Crystallodytes, and 9 in 
Hypoptychus. Of these, all are segmented in 
Tripterygion and the ammodytoids; however, 
there is a small, unsegmented, splintlike upper- 
Fig. 6. Caudal skeletons of a, Parapercis schauins- 
landi; b, Tripterygion atriceps; c, Bleekeria gilli; and 
d, Hypoptychus dybowskii. ce, Centrum; ep, epural; 
hr, hemal arch; hs, hemal spine; hy, hypural; na, 
neural arch; ns, neural spine; un, uroneural; and ur, 
urostyle. 
