712 
SCANDINAVIAN FISHES. 
The Loach is generally a little larger than the pre- 
ceding species. In Scandinavia and Western and North- 
ern Europe it seems never to attain a greater size than 
10 — 13 cm. In the Crimea, however, according to 
Pallas, it may sometimes measure nearly half a foot 
(about 16 cm.); and in the mountain brooks of Persia, 
lie says, it attains a still greater size. The largest 
specimens we have examined were from Finland and 
measured 112 mm. in length. 
The body is in front more or less terete, behind 
more and more compressed. The head is entirely diffe- 
rent in form from that of the preceding species, but 
the rest of the body is of almost exactly the same shape, 
the tail being only slightly shallower than the forepart 
of the body. The greatest depth of the body measures 
between 13 and 11 % (10 1 / 2 %) and the least depth of 
the peduncle of the tail between about 7 and 87 2 % 
of the length of the body. 
The length of the head is about 20 — 18 % a of that 
of the body. Seen from above it is almost parabolical. 
It is also broader than in the preceding species, some- 
what depressed, flattened at the top, with sloping facial 
line and blunt snout. Underneath it is broad, flat, and 
even. The entire head is scaleless; but the skin is here 
finely granulated, the canals of the system of the lateral 
line being marked by several rows of small, raised 
tubercles, each pierced with a duct. One row, thin and 
almost double, runs below the eye from the upper 
rostral barbel to the lateral line. Another roAv, con- 
taining some few pores, runs above each eye and the 
nostrils. A third row coasts the margin of the pre- 
operculum and follows the under surface of the lower 
jaw. A transverse canal across the occiput may also be 
traced in three scattered pores, set in a row. The eyes 
are small and somewhat oblong, their longitudinal dia- 
meter in specimens between 87 and 112 mm. long being 
about 16 % of the length of the head. The orbits are 
distinctly bounded by a dermal fold ( oculi liberi, Blee- 
ker). They are set high, at the sides of the flat fore- 
head, separated by a distance of about three times their 
vertical diameter, and at a distance from the tip of the 
snout at least (in our specimens) a little greater than 
the postorbital length of the head, which length in young 
specimens is almost equal to the breadth of the head 
at the eyes, in older ones perceptibly less. The cheeks 
are soft and fleshy, without spine or hollow depression. 
The nostrils lie just in front of the eyes, each lateral 
pair being so close together that the anterior nostril 
does not extend half-way from the eyes to the tip of 
the snout. The posterior is the larger and simple, the 
anterior has a raised, tubular margin, which projects 
behind in a point and thus resembles in form a quill 
pen. The mouth lies, as in the preceding species, under 
the tip of the snout and is very small and transversely 
set. The lips are thick, and the upper seems double, 
as in so many other fishes, this being due to the for- 
mation of an upper fold by the projecting skin of the 
snout itself, in addition to the fold starting from the 
intermaxillary bones. These two folds send out, as in 
the preceding species, 6 thick, soft barbels, so arranged 
that two pairs originate from the under surface of the 
upper fold, the smaller pair at the very tip of the snout 
and the other pair just behind this point; while the 
third pair starts from the very corners of the mouth 
and contains the largest barbels, their length being a 
little more than V 3 of that of the head. The underlip 
is more fleshy and at the middle — often on the sides 
as Avell — cloven or divided into lobes. The gill-open- 
ings are small, the branchiostegal membrane passing, in 
the same Avay as in the Spined Loach, into the skin of 
the belly just beloAv the base of each pectoral tin, so 
that the openings are separated by the entire breadth 
of the broad, flat breast. This membrane contains 3 
long, but not broad rays, Avhich extend almost below 
the tip of the operculum. The operculum itself as Avell 
as the small, oblong suboperculum is distinct; the other 
opercular bones are Avell covered by the thick skin. 
The apparatus of the branchial arches exhibits in the 
form of the urohyoid bone a striking resemblance to 
the corresponding bones in the Sheatfish. 
The dorsal tin begins someAvhat in front of the middle 
of the entire length of the body, or about half-Avay — 
sometimes a little farther back — along the body minus 
the caudal fin: the distance betAveen this tin and the tip 
of the snout measures in our specimens about 42— 48 % 
of the entire length of the body, 48 — 55 % of the length 
of the body excluding the caudal fin, or 65 — 71 % of the 
distance betAveen the anal tin and the tip of the snout. 
The length of its longest ray is about equal to the 
greatest depth of the body or someAvhat greater than 
this depth, and is much greater than the length of the 
base of the tin, Avhich seems as a rule to vary betAveen 
19 — • 1 6 ' G %, according to Canestrini’s measurements. 
