ROACH. 
775 
hooked tip, the others strongly curved at the tip, more 
or less compressed in a transverse direction (back and 
Iront), and before they are worn, more or less distinctly 
crenulated (pectinated), the hindmost tooth, which is 
the least worn, most distinctly. Sometimes only a trace 
of this crenulation remains, in the form of small pro- 
tuberances on the masticatory surface, which is eventu- 
ally hollowed into a smooth, simple furrow. A strik- 
ing difference between the pharyngeals of the Roach 
and those of the preceding Leuciscines, and a point that 
calls to mind the Tench, is the prolongation common to 
the bases of the posterior teeth, the last two or three 
being set on a process jutting from the pharyngeal 
bone into the pharynx. The heart-shaped pharyngeal 
cartilage of the three preceding species is modified here, 
this organ being elongated into a tongue-like form, with 
the anterior (upper) end obtusely rounded, and the 
posterior, tapering extremity only slightly folded and j 
elevated, scarcely marked off from the other part. 
The dorsal fin, which is particularly remarkable 
for its height, is obliquely truncate at the margin, with 
pointed corners, especially behind. It begins at a di- 
stance from the tip of the snout that- increases with 
age and measures about 44 1 / 2 — 487 2 % of the length 
of the body, or half the length to the base of the caudal 
fin. This distance is on an average less than in any 
of the three preceding species. In this respect the Roach 
comes nearest to the Cyprinine group; and the other 
Leuciscines have evidently followed a special direction 
of development from that group, reaching different 
stages. The Dace has advanced furthest, as shown by 
the table given below". The base of the dorsal fin 
measures about 14 — 12 %, its height about 20 1 / 2 — 17 , 
%, of the length of the body. The anal fin, the di- 
stance between which and the tip of the snout is about 
63 — 68 % of the length of the body, resembles in form 
that of the Ide. The length of its base is about 12 — 
1 0 1 2 %, its height about 137* — 107 2 of the length 
of the body. The caudal fin is rather deeply forked, 
its middle rays occupying about 9 — 8 % of the length 
of the body and measuring about 36 — 40 % of that of 
the longest caudal rays. 
The pectoral and ventral fins have the same form 
as in the Ide, but differ only slightly in length, that 
of the former varying between about 17 and 147 2 %, 
that of the latter between 17 and 14 %, of the length 
of the body. The distance between the ventral fins and 
the tip of the snout measures about 43 — 47 %, the pre- 
abdominal length about 22 — 25 %, and the postabdo- 
minal length about 20 — 22 %, of the length of the body. 
The scales resemble those of the three preceding spe- 
cies, but are comparatively much larger than the Ide’s, 
and as a rule larger even than the Chub’s, a point which 
is shown by the above estimates of their number in the 
lateral line and in a transverse row between the dorsal 
and ventral fins. During the spawning-season they are 
destitute of the rim then present round the scales of 
the Ide, but are strewn in the male with the usual, 
pointed, verrucQse tubercles. 
The sexes are distinguished only by the more 
slender body of the male and the said spiniferous tu- 
bercles, which are scattered during the spawning-season 
on the skin of the head, the opercula, the scales co- 
vering the forepart of the body, and the first ray of 
the pectoral fins. According to a note on v. Wright’s 
original, our figure represents a male without this ex- 
ternal sexual character. 
The upper part of the head and back is of a, dark, 
blackish green, which rapidly passes below into brighter 
green, and then gradually into the lustrous silvery gray 
of the sides, which at the middle are faintly tinged 
with bronze and towards the belly shade into yellow. 
Each of the scales is marked at the base with a green- 
ish spot, darker on the uppermost scales, gradually fad- 
ing and at last disappearing on the lower ones. In the 
lateral line the scales are furnished with two similar, 
but smaller spots, lying one on each side of the duct, 
which is yellowish. In some specimens the iris is of 
a 
Aver a g c*. 
Leuciscus rutilus. 
Leuciscus cephalus. 
Leuciscus idus. 
Leuciscus 
grislagine. 
3 specimens 
102 — 153 mm. 
long. 
3 specimens 
167 — 327 min. 
long. 
5 specimens 
37 — 89 mm. 
long. 
6 specimens 
170 — 196 mm. 
long. 
5 specimens 
244 — 424 mm. 
long. 
4 specimens 
84 — 148 mm. 
long. 
4 specimens 
181 — 416 mm. 
long. 
5 specimens 
178 — 314 mm. 
long. 
Length of the body expressed in millimetres 
127 
224.7 
67.4 
183.4 
297.8 
124 
305 
196.2 
Distance between the dorsal fin and the tip of the 
snout in % of the length of the body 
45.8 
47.7 
48.1 
48.4 
49.o 
49.8 
50. o 
50.4 
98 
Scandinavian Fishes. 
