7(1 1 



fycitciscus vnli/'iri!'. Flmno, lirit. Am'm., p. 187; Cuv., \'ai.., 

 /list. iVfl/. Poifs., vol. XVII, p. 202 (+ Lem: rostratns 

 (ex. Ag.\ss.) + L. rorhiii' (ex. Agass.) + L. laiicasti-iensis, 

 (ex. SirAw), p. '21i; + y.. hnrdiiialeiii'is, p. 218, iiec L. ym- 

 /uji'/ie, p. 220): Gtiu:, Vat. Brit. 3fm.. Fisli.. vol. VII, p. 

 220; Day, Fish. Gt. Brit.. In-!., vol. 11. p. ISO, tab. 

 CXX.KIII, li,s. 1; Muh.. HcKE. Fi.",?!,. (/.*/,«., p. 10!l. 



The 1>;k'c' is oiu' of llie smaller species of the ye- 

 mis. Its ordin.-irv length is between 1') :nn\ '_'() ciu., 

 ;uicl ill Sweden |)rol)al)l\' does not exceed "i") em. 

 Further sonth it .seems to attain a somewhat j^reater 

 size; Fa'I'io found in the Rhine a gravid female of this 

 species, "27') mm. long and 300 grammes in weight. 

 Day .states that in the Thames the l)aee attains a length 

 of about o dm. 



Of all tiie Scandinavian sjiet'ies within the Leueis- 

 cine subfamih' the Dace is the most elongated in pro- 

 portion to the dejith of the body, and is easily i-eeog- 

 nised 1)V this character. The body is deepest a little 

 in front of the dorsal fin, and the greatest depth mea- 

 sures in adult specimens, 18 — 21 cm. long, about 21 

 — 24 % of the length of the body. In younger speci- 

 mens the greatest depth is even relatively les.s, as else- 

 where in the family. The least depth of the body (of 

 the peduncle of the tail) measures in adult specimens 

 about 8V., — 7' ., "» of its length. The back is terete, 

 though less so just in front of the dorsal tin, and the 

 sides are moderately compressed. The back rises in a 

 gradual curve from the head to a point a little in front 

 of the dorsal tin, though it is straighter than in the 

 Scaudina^■ian congeners of the Dace, and the cur\e does 

 not increase in sliarpness at the occiput. From this 

 point the dorsal profile slopes gently, almost in a sti-aight 

 line, to the base of the caudal fin. The ventral profile 

 forms a similar or even more gradual curve from the 

 chin to the \'ent. \\-hich iirotrudes slightly, ;in(l then 

 runs straight to the caudal fin. 



The head is of moderate size (in adult specimens 

 about 21 — 19 % of the length of the body), with broad 

 and rather fiat forehead, sloping with a slight convexity 

 towards the broad and very obtuse snout, which pro- 



The length of the u])i)er jaw iVom the middle of the 

 tip of the .snout measures in adult specimens rather 

 more than ' , (about 2.V,,,— 2« %) of that of the head. 

 TIk^ length of the lower jaw is e(pial to or somewhat 

 greater than that of the snout, or about ';., (32—35?^) 

 of that of the head. The eyes are fairly large, their 

 longitudinal diameter being only slightly less than ' , 

 (about 23 — 24' , '-i-) of the length Of the head. They 

 iU'e generally s<'t just in tVont of the middle of the 

 head" and so high that the line drawn from the middle 

 of the caudal lin to tiie margin of the upper jaw 

 touches the inferior margin of the eye. The least 

 breadth of the intemrbital space is about '/a ('^^'/e — 

 34 %, exceptionally 37 %-,) of the length of tlie head, or 

 I'/j — 1' .J times the longitudinal diameter of the eyes. 

 The nostrils are rather large, and lie in a dee|i cavity, 

 nearer to the eye than to the tip of the snout. Th<' 

 gill-rakers are small and scattered, Init jiointed, num- 

 bering 8 in the outer row on the first branchial arch 

 and 7 on the pharyngeal bones, l^ach pharyngeal is 

 armed as a rule with 7 teeth (fig. 1810- set in two 

 rows. The inner row contains .') long and faii'ly straight 

 teeth, curved upwards at the tij), but usually not much 

 hooked'', and without incisions or spines on the indi- 

 stinct masticatory surface. The teeth in the outer row- 

 are generally 2, sometimes 3, in number, short, straight, 

 and conical. The pharyngeal cartilage is soft, thin at 

 the edges, heart-shaped, and deciduous. The gill- 

 o])enings do not extend at all al)ove the upper margin 

 of the gill-cover, and lielow they coalesce with the 

 isthmus at a distance from each other of about half 

 the diameter of the eyes. 



The dorsal fin, the height of which is greater than 

 its length at the base, has an ol)li<|ueh- truncate mar- 

 gin \vith somewhat roniuled corners. ISehind it is lialt 

 as high as in front, a rule which a[iplies to most of the 

 Li'ticisc'DKC. It begins at a distance from the tij) of the 

 snout which in adult specimens measures on an average 

 half the length of the bodv, varying, ho\\-ever, between 

 4()',2 and 54 % thereof. Its base occupies ', i„ (varying 



jects a little in front of the jaws. The mouth is small in our specimens between it' ,, and 10\., %) of the length 



and turns slightly upwards, as in the rest of the 7.c«- of the body; and its height (the length of the longest 



ciscinre. the upi)er jaw is slightly more prominent than ray), which is as a rule ccpial to the length of the 



the lower, and the corners of the mouth extend a little jiectoral fins, varies in our specimens between 1.') and 



behind the perpendicular from the posterior nostril. Ki' , ".. f>f the length of the body. The fir.st three rays 



in onr speciinens between 48 



and 



of its entire lenatli, the variations essentially 



" The postorbital length of the head varies 

 depending on the breadth of the opercular rini. 



' In specimens from Lake Wener, however, we lind the hooked tij.s well develojied in the two hin<lniosl teeth of this row. 



