curve of tlie back becomes more elevated, wliile tlie 

 ventral ijrolilc is rendered morc^ or less straight. In 

 front tiic doi'sal margin is broadly convex or, on the 

 head, even flat; but towards the beginning of the dorsal 

 fin it graduaih" bei-omes more or less compressed; be- 

 hind the dorsal fin it is again flattened. The ventral 

 niariiin in front of the anal fin is broadly convex, at 

 the ventral tins even flat; behind the anal fin it is fiat, 

 like the dorsal margin of the peduncle of the tail. The 

 sides of tlie body are slightly convex. 



The length of the head from the articular knobs 

 of the maxillaries is about equal to the greatest depth 

 of the l)od\', but vai'ies conversely to tile latter, from 

 about 21 to 20 % of the length of the body in young 

 Grayling, and from 20 to 18' ., % thereof in old. The 

 head is wedge-shaped, with compi-essed or only slightly 

 terete cheeks. The most characteristic feature in its ' 

 appearance consists in the shallow (sometimes even sharp) 

 and broad tip of the snout, which in a horizontal di- 

 rection is truncate or slightly curved, but is occasionally 

 somewhat prolongated like a beak, if only to a short 

 distance, and which, when the mouth is closed, always 

 projects beyond the point of the lower jaw. The eyes 

 show the ])eculiarity that the pupil, as in the G\vyniads, 

 is anteriorly somewhat pointed, at an angle. Their size 

 varies with age, the longitudinal diameter being in 

 young specimens about 29 %, in old about 16 %, of 

 the length of the head. The nostrils are set somewhat 

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

 anterior on each side being raised in a tubular form, 

 the posterior, which lies just liehiiid, resemliling a trans- 

 verse slit, covered by a dermal fold from in front. The 

 lips are quite fleshy, especially on the intermaxillai'ies; 

 and the form of the broad, but short gape is essentially 

 determined l)v the said bones. These bones are reduced 

 each to a thin, triangular disk, transversely set and 

 consisting principally of the articular process, only the 

 lower, toothed margin, which is also the true corpus 

 of the bone, being somewliat thickened. The maxil- 

 laries are terete in the anterior, inward [)art (the ar- 

 ticular process); but behind this point they are disk- 

 shaped, curved like a sword, but of fairly uniform 

 breadth. The teeth extend along about the middle 

 third of their inferior margin. The oblong jugal bone 

 is about "/s as long and ',2 as broad as the maxillarj'. 

 The length of the maxillaries is less than in any pre- 

 ceding Salmonoid genus, varying between 35 and 27 % 

 of that of the head, or between 48 and 38 % of that 



of tlu! head reduced. Togetiier with tlie jugal bone 

 the uiaxillar\- bone varies in l)rcadlli between about 

 ',', (in the voung) and ^ ^ (in old specimens) of its 

 leiigtii. Thc^ lower jaw is deep at the middle, but at 

 tlie broad anterior margin shaiiow, almost sharp. Its 

 length is about 54 — 48 % of that of the head or 76 

 — 66 % of that of the head reduced. The disti-ibution 

 of tlie teeth ill tlie iiioutii and jiliarynx we liave al- 

 read\- touched upon. The teeth are ail alike, of a 

 blunt conical or e\lindrical shape, in contradistinction 

 to the pointed and more or less curved teeth of the 

 ])r<!ceding genera. The characteristic features of the 

 gill-rakers we have also noticed. In the upper jaw 

 we find a well-develoj)ed transverse fold (palatal cur- 

 tain), ]iartially concealing the vomerine teeth, behind 

 the intermaxillary teeth. The lower jaw is not with- 

 out a similar fold, but this is very low. The pseudo- 

 branchiae are rather large, the length of their longest 

 lamella (at the middle) being about equal to the vei'- 

 tical diameter of the pupil. Tiie gill-openings are 

 large, extending from tlie middle of the ui)per oper- 

 cular margin down to the istlimus in about a line with 

 the anterior margin of the eye, where they cross each 

 other for a little distance, the left fitting into the 

 double fold of the right, as we have observed in Mal- 

 lotus. All the branchiostegal rays are flat, the anterior 

 (lower) curved in an ensiforin shape. Behind they 

 gradually increase both in length and breadth. The 

 operculum is obliquely quadrangular, wath the upper 

 posterior corner rounded, the posterior margin more 

 or less concave, and the inferior margin oblicpiely 

 ascending in a backward direction along the suboper- 

 culum, the length of which measures at this margin 

 about 26 — 31 ?» of that of the head, and the breadth 

 (height) of which is about half that of the operculum. 

 The lower posterior corner of the suboperculum is 

 shai-ply rounded. The hind margin of the preoper- 

 culum is broad, and its lower posterior corner almost 

 rectangular. 



The dorsal tin begins at a distance from the tip 

 of the snout (the articular knobs of the maxillaries) 

 that measures on an average 36 — 34 % (exceptionally 

 38 or 33 %) of the length of the body. The average 

 length of its liase, which increases even relatively with 

 age and is greater as a rule in the males than in the 

 females, varies between about 18 and 28'/2 % (in old 

 males exceptionally 25 %) of that of the body. Its 

 shape shows great variations. Sometimes (especially 



