CRUCIAN CARP. 
737 
branchiostegal membranes coalesce with the sides of the 
isthmus, at a distance from each other which is equal 
in old specimens to the longitudinal diameter of the 
eye. The size of the gill-openings is consequently not 
very considerable, . though greater than in the Carp, 
the head being much deeper. The branchiostegal mem- 
brane forms a broad, membranous rim, usually broader 
than in the Carp, along the margins of the operculum 
and suboperculum. The gill-rakers are of the same 
soft structure as in the Carp, but more numerous, the 
outer row on the front of the first branchial arch con- 
taining about 26 — 30. The lower pharyngeals are 
furnished at the outer margin with about 19 si- 
milar but shorter spines. At the inner margin they 
have a short row of four teeth (fig. 182), the first of 
which pretty closely resembles the corresponding tooth 
in the Carp, being terete, or even somewhat compressed 
at the sides, but with hooked tip and obliquely cut 
crown. The three posterior teeth, on the other hand, 
are strongly compressed in a transversal direction (in 
front and behind), and their crowns are bent close to 
each other. The pharyngeal cartilage has about the 
same triangular shape as in the Carp. 
The body is covered with large, imbricated, and 
striated scales, resembling in essential respects those of 
the Carp, but with the radiating grooves on the co- 
vered (anterior) part of each scale more distinct and 
opening in sharp sinuses at the anterior margin of the 
scale. As a rule six (4 — 8) grooves appear at this 
margin. Another groove usually runs straight or ob- 
liquely across the scale, and from the middle of this 
groove (the indistinct nucleus of the scale) two or three 
similar grooves extend obliquely backwards along the 
free (posterior) part of the scale, where the concentric 
stria; show undulating breaks. The hind margin of the 
scale thus displays numerous and fine, but irregular 
notches. The lateral line is straight or slightly sloping, 
and lies somewhat nearer to the ventral edge than to 
the dorsal. It is covered by 33 (31 — 35) scales. It 
terminates sometimes at the middle of the bodv, more 
frequently above the vent; and is seldom complete all 
the way to the caudal fin. The perforating ducts of 
the lateral line are still shorter than in the Carp. In 
most cases we find 7 rows of scales above the lateral 
line and 6 below it. Sometimes there are 8 rows above 
and 7 below, in which case the top and bottom rows 
consist of smaller scales. The vent lies somewhat be- 
hind the beginning of the hindmost third of the bod}'. 
The dorsal fin is long, but shorter than in the 
Carp, though its length undergoes even relative increase 
with age, varying between about 26 and 32 % of that 
of the body. Its height, on the other hand, is generally 
greater than in the Carp, being apparently subject to 
greater individual variation (about 14 — 18 % of the 
length of the body). It begins as far from the tip of 
the snout as from the base of the caudal fin, or a litfle 
nearer the latter, exactly above the bases of the ventral 
fins, or a little farther forward, and ends in most cases 
above the middle or the termination of the anal fin. 
Its height is almost uniform, or slightly greater in the 
anterior half; and its margin is arcuate in adult spe- 
cimens, straighter in the young. The rays vary in 
number between 20 and 23. The first four rays are 
simple, the first of all being an almost imperceptible 
spine, most often hidden in the skin, the second some- 
what longer, the third more than twice as long as the 
second, and the fourth dentated behind on both sides, 
soft at the tip, and nearly as long as the first branched 
ray. The last ray is cloven to the base, and may 
easily be counted twice over. 
The anal fin is short but fairly high, with rounded 
margin. Its length is about 10 or 11 %, its height 
about 12 or 13 % of the length of the body. It con- 
tains 9 or 10 rays, the first three simple. The first is 
a rather small spine, the second twice as long as the 
first, the third thick and hard, with soft and jointed 
tip, dentated behind on both sides, and somewhat shorter 
than the first branched ray. The last branched ray is 
cloven to the base. 
The pectoral fins are obliquely rounded at the tip, 
and contain 1 simple and (in most cases) 14 branched 
rays. Their length may rise from 14 to 18 % of that 
of the body. The ventral fins are both broader and 
longer, being more obliquely rounded at the tip. Their 
length varies between 16 and 19 % of that of the body. 
Here, as in the preceding forms, the first ray is short 
and set very close to the second, which is thick and 
hard, with soft tip, and nearly as long as the first 
branched rays. Both pectoral and ventral fins are 
generally longer in the males than in the females. 
The caudal fin is broad, when folded somewhaf 
forked, almost truncate when expanded. The middle rays 
occupy 13 — 18 % of the length of the body, and in adult 
specimens are 2 / 3 as long as the longest lateral rays. 
The colouring of the Lake Crucian Carp is very 
variable, and is closely connected with the nature of 
