Tlu' Iilc is "lie iif the lartrcr s]K.H'i('s within <i:is 

 U'ciuis. Acconliiii;' in llic reports sent in to the Swedisli 

 Fisiieries Connnittce of ISS], it attains in Sweden a 

 lengtii ot ahout 11 (ini. and a weight of (!'/■ k<i'ni. These 

 statC'inents, iiowcNcr. undonhtedly ret'ei' to exeeptions, 

 unless tiiey are exaggerated, or pej-ha|)S de])end on a 

 coni'nsion of this species with the Asp (Aspiiis rajia.r). 

 The oi'dinar\- K'liglh of th<' Me in an adnit state is 

 about M or 4 dm. At a lengtii of o dm. it weiiiiis 

 at most from 2 to l>' ., kgni. 



Tlie liody is moderately compressed or even ratlier 

 hu]l<\'. Tiie greatest deptii, whicii lies just iu front of 

 the Ix'ginning of tlie dorsal tin, usually uu'asures in 

 vouug specimens rather more than ' j, in old 25 — 30 "i, 

 of tlie length of tlu' l)od\-, and tlie greatest hreadth or 

 thickness is not quite half the depth. The latter measure- 

 ment varies, however, accordin<i- to sex, age, or season, 

 in voung s))ecimens being sometimes only about " - ot 

 the depth, and rising in old specimens to about 45 — 

 51 % thereof. The least depth of the body is in young 

 specimens about 10 % (9' ., %). in old about 11 %, of 

 its length. The l)ai'k, which is fairl\- broad and convex, 

 and which rises more or less abruptly, according to the 

 fatness of the fish, from the occiput, forms a slight 

 upward curve. The belly from the istlunus to the vent 

 is fairh' straight, except during the siiawning-season, 

 when it forms in the female a down\vard curve, be- 

 ginning at the chin, lietweeii the pectoral and ventral 

 fins the l)elly is Hat, but subsequently, between the 

 latter and the vent, becomes convex and somewhat 

 carinated. 



The length of the head usually occupies in mode- 

 rate-sized si)ecimens a little more than '4 (SS^', — 21'/.,%) 

 of that of tlie bod\'. In old specimens this jn'oportioii 

 is almost exactly '/-, and in voung ones the head is 

 as usual larger in comparistm with the rest of the body. 

 The front part of the head is broad and convex, forming 

 a <,n'adual curve from the snout to a point somewhat 

 in front of the nostrils, where it is slightly depressed". 

 The breadth of the interorbital space increases, even 

 relatively, \\itli ai;e from a little more' than 37 % to 

 nearly 4(i % of the length of the head, the lattei- in 

 specimens 4 oi- 5 dm. hnig. As a rule, however, this 

 breadth is less than ^ ^ of the base of the dorsal fin, 

 and we have never found it to exceed 85 % thereof. 



;. 765 



The sides of the head are somewhat compressed and 

 llatleiicd. The snout is iiliint, liroad, and only slightly 

 projecting, the margin of the n|iper jaw (middle of the 

 intcrniaxillari(!s) being the most prominent point. The 

 mouth is small and turned sli;;htlv upwards. In full- 

 grown specimens the corners of the mouth do not e.x- 

 tend behind the pei-jiendicular from the middle point 

 between the e\e and the nostrils, while in ^•oung spe- 

 cimens tlie\' i-eacli (•()mparativelv a little further back, 

 nv to a line with the anti'i'ior margin of the eye. The 

 length both of the snout and the upjicr jaw increases, 

 even comparatively, with age, nio>t, however, in the 

 former cast'; the length of the snout increasing in s])e- 

 cimens 8 — 42 cm. long from about 27 to ?,A % of the 

 lengtii of the head, and that of the u|)per jaw from 

 about 27 to ?>\ % of the same. A retrogression to the 

 characters of youth may sometimes be found, however, 

 in old specimens. When the mouth is openeil, the 

 upper jaw is slightly protruded. The length ot the 

 lower jaw measures about 36 — 40 % of that of the head. 

 The longitudinal diameter of the eyes decreases compa- 

 ratively, during growth, in the above-mentioned speci- 

 mens, from about 30 t(j 15 % of the length of the head, 

 i. e. from a little less than the breadth of the inter- 

 (u-bital space to only '.. thereof. At the same time 

 the postm-bital length of the lu-a.d increases from some- 

 what less than ' , to about 511 % of its entire length. 

 The nostrils are set, as usual in the genus, close to 

 each other and nearer to the eye than to the tip of the 

 snout, the narrow partition-wall between them being 

 elevated into a kind of lobe. The anterior nostril is 

 round, the posterior crescent-shaped and larger. The 

 distance between the two anterior nostrils is about half 

 the breadth of the interorbital space. As usual in the 

 genus, the head is scaleless, and is covered on the sides 

 with a thin, transparent skin, through which the oper- 

 cular and facial bones are distinctly visible. The occiput 

 and forehead, on the other hand, are clothed with a 

 thicker, firmer, and richly niuciferous skin, whicli has 

 a smooth and even surface. The branchiostegal mem- 

 brane extends behind tlie ;:ill-co\er in a broad rim; 

 its three rays are fiat, broad, and curved; and below, 

 as is usually the case in the genus, it is united to the 

 isthmus, in a line with the hind margin of the ])re- 

 opercnlum. The |iseudobranchi;e are well-developed. 



" Willi regard to tliis depression see above, p. 716. note a. 

 '' In exoeptionnl cases a little less. 



