744 



SCANDINAVIAN 1-ISUES. 



- — and which in its most advanced development has | obli(|uely hooked at the tij). The pharyngeal cartilage 



given I'ise to thi; estal)lishment of a distinct species, | is soft, scarcely cartilaginous, and triangular, with the 



Gobio ohtusirostris. This swelling — e\en when it is I upper (anterior) side slightly curved upwards (convex). 



not very prominent — and also the projection beyond j The pseudol)ranchiffi are distinct on the inside of the 



the mouth of the blunt tij) of the snout most strongly ] upper part of the hyomandibularbone, though small, 



characterize tlie head of tlie (iudge(Mi. Tlic lerigtii of i with about (1 filamentous lamelke. Tiic o])crculum is 



the head varies between nl)out '/, and a little more | traitezoidal, its u])per and lower sides being parallel, 



than \i'. (-26 — 22 %) of tiiat of the bod\-, being as usual 

 comparatively greater during youtli. The eyes are ex- 

 tremely mobile, round, set fairh' high — their upper 

 margin being almost in a |)lane Avith the slightly con- 

 vex forehead — and rather large, their longitudinal 

 diameter varying l)etween about 7 and 472 ^» of ^'^^ 

 length of the body or about 27 and 21 ?«; of the length 

 of the head. In young specimens this longitudinal dia- 

 meter is about equal to the In-eadtii of tiie interorbital 

 space, in old less, sometimes only '/j„ thereof. The posi- 

 tion of tlie eyes is also such that the length of the snout 

 — with considerable individual variations" — measures 

 on an average "'r, of that of the head. The nostrils lie 

 on tlie rounded margin between the sides and back of 

 the snout, much nearer to the eyes than to the tip of the 

 snout. Together they form on each side a round cavity, 

 divided externally by the obli(pie ])artition \vall l)etween 

 them, which is raised into a lid. The mouth is small 

 and lies, as we have mentioned, entirely on the under 

 sid<' of tlie head, witli the maxillary l)ones extending 

 back to about a line \\ith tlie anterior nostrils and 



but the former only about ^, ., as long as the latter and 

 throughout united to the dorsal side. The branchiostegal 

 membrane is extraordinarily narrow along the hind 

 margin of tlie opei-culum, but all the broader along the 

 suboperculum and in its lower part, where it is ex- 

 tended by three, fairly broad, sabre-shaped rays. The 

 height of the gill-openings is about equal to the post- 

 orbital length of the head; their upper angle lies hardly 

 on a level \vith the sujierior margin of the eye, and 

 their lower angle lies in aliout a line with the hind 

 margin of the preoperculum, where the branchiostegal 

 memliranes on the ventral side coalesce with the 

 isthmus. 



The dorsal tin is trajiezoidal, with the upjier mar- 

 gin straight or slightly concave and the high anterior 

 margin composed of the first three (simiile) rays. The 

 first of these rays is extremely short, sometimes scar- 

 cely possible of external detection, while the second is 

 nearly half as long as the third. The tin begins at a 

 distance from the tip of the snout which measures on 

 an average 42 % (varying between 41 and 43 %) of 



with the articulation of the lo\\er jaw in a line with I the length of the body, and its length (base) is 11 or 



the anterior margin of the orbit. The lips are fleshy, 

 and the dermal fold that lies on each maxillary bone 

 is elimgated behind into a liarbel of moderate length, 

 which extends when laid back hardlj' any distance, if 

 at all, behind the perpendicular from the anterior mar- 

 gin of the eye*. The palatal cui-taiii within the upper 

 jaw is well-developed. The tongue is fleshy, but hardly 

 at all free from the bottom of the mouth. The gill- 

 rakers are short, scattered, blunt, and soft, developed 

 on the flrst branchial arch only in the inner (posterior) 

 row, which contains al)out 8. Among the pharyngeal 

 teeth (flg. 186) only the three posterior in the inner 

 row have a distinct, obliquely cut masticatory surface. 



12 % (in the males sometimes nearly 13 %) of the 

 same. Its height (the length of the third ray) is always 

 greater than its length and varies between aliout 16 

 and 21 % of the length of the body. 



The anal fln is of the same form and structure as 

 the dorsal. Its distance from the tip of the snout is 

 on an average 62 % (varying between 60 and 63 %), 

 its length 7'/„ % (varying between 7 and S' ^ ?^), and 

 its height 13^.; % (varying l)etween 12 and 16 ?») of 

 the length of the body. 



The caudal fln is deejily forked at the hind mar- 

 gin, most so in old specimens, and thus forms an ob- 

 tuse aiiirlc with somewhat convex edsres to tlie lobes. 



while the others — lioth the two anteri(jr, thicker teeth 1 The length of the middle rays, which occupy about 

 in the inner row and the two or three teeth in the { 11 — 9 % of the length of the body, is as a rule in 

 outer row — are of a straighter cylindrical form, though 1 young specimens equal to or a little more than hall. 



" Varying between 34 and 46 "„ of tlie lengtli of tlie lieiid. 

 ' Ganestrini, however, inrntions a specimen, a male 74 '\, mm. long 

 half that of the head. 



vhich the length of the barbels was somewliat more than 



