'12 



SCANDINAVIAN nsiIES. 



The Loach is generally a little larger than the jire- 

 cecling species. In Scandinavia and Western and Xortli- 

 erii Europe it seems never to attain a greater size tiian 

 10 — 13 cm. In the Crimea, liowcvcr, according to 

 Pallas, it may sometimes measui'c nearly half a foot 

 (aliotit ir. cm.); and in the mountain brooks of Persia, 

 he 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 ])receding species, but 

 the rest of the Ijody is of almost exactly tiie 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''., "») and the least depth of 

 tile peduncle of the tail between aliout 7 and 8''., % 

 of the length of the body. 



The length of the head is about 20 — 18 %>" of that 

 of the body. Seen from above it is almost parabolical. 

 It is also broader than in tiie preceding s])ecies, 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 liere 

 tinely granulated, the canals of the system of the lateral 

 line being marked l)y several rows of small, raised 

 tubercles, each pierced with a duct. One row, thin and 

 almost double, runs below tlie eye from the upper 

 rostral barbel to the lateral line. Another row, con- 

 taining some few pores, rims above each eye and the 

 nostrils. A third row coasts tlie margin of the prc- 

 operculum and tVjllows the under surface of the lower 

 jaw. A transverse canal across the occiput maj' also be 

 trace<l in three scattered pores, set in a row. The e3'es 

 are small and somewhat oblong, their longitudinal dia- 

 meter in specimens between 87 and 112 mm. long being 

 about Hi % of the length of tlie head. Tlie orbits are 

 distinctly b(mnded l:)y a dermal fold {ochVi liberi, 15lee- 

 liEu). They are set high, at tlie 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 lai'ger and simple, the 

 anterior lias a raised, tubular margin, which projects 

 behind in a point and thus resembles in form a quill 

 pen. Tiie mouth lies, as in the preceding species, under 

 the ti]) of the snout and is very small and transversely 

 set. The lijis are thick, and the upper seems double, 

 as in so many other flshes, 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, <o thick, soft liarbels, so arranged 

 that tw(j jiairs originate from the under surface of the 

 upper fold, the smaller pair at the very tij) of the snout 

 and the other pair just behind this jioint; while the 

 third pail- stai-ts from the \ery corners of the mouth 

 and contains the largest barbels, their length being a 

 little more than 'Ai of that of the head. The underlip 

 is more fleshy and at the middle — often on the sides 

 as well — cloven or divided into hjbes. The gill-open- 

 ings are small, the branchiostegal membrane passing, in 

 the same waj' as in the Spined Loach, into the skin of 

 the belly just lielow the base of each pectoral flu, so 

 that the oiienings are separated by the entire breadth 

 of the broad, flat breast. This membrane contains 3 

 long, but not broad rays, which extend almost below 

 the tip (jf the operculum. The operculum itself as well 

 as the small, oblong suboperculum is distinct; the other 

 opercular bones are well covered Ijy the thick skin. 

 The apparatus of the branchial arches exhibits in the 

 form of the urohyoid bone a striking reseinlilance to 

 the t'orresponding bones in the Sheatflsh. 



The dorsal fln begins somewhat in front of the middle 

 of the entire length of the bodj', or about half-way — 

 sometimes a little farther liack — along the body minus 

 the caudal fln: the distance lietweeii this fln and the tip 

 of the snout measures in our specimens about 42— 48 5K 

 of the entire length of the body, 48 — 55 % of the length 

 of the body excluding the caudal fln. or (55 — 71 % of the 

 distance between the anal fln and the tip of the snout. 

 The length of its longest ray is about ecjual to the 

 greatest depth of the body or somewhat greatei- than 

 this depth, and is much greater than the length of the 

 base of the fln, which seems as a rule to vary between 



19 — IC'C %, accorJiiig to Canestiuni's measurements. 



