77r) 



hooked tip, tlie others .stroiiol}' our\ed at flic ti]), iiuirc 

 or less compressed in a transverse direetiim (hack and 

 front), and lidore thev arc woi-n. nnirc or Ics.s distincth' 

 crenulated (|i<H-tinatcd), tltv hindnm.st tooth, whidi is 

 the least worn, most distinrtJx'. Sometimes ()id\ a trace 

 of this crenulation remains, in tiie form of small pro- 

 tuberances on tlie masticatory surface, which is eventn- 

 ally hollowed into a smooth, simple furrow. A strik- 

 ino' difl'erence between tlie pharyngeal.s of the lloach 

 and tliose ot the jireceding Leuciscines, and a jioint that 

 calls to niinil the Tench, is the prolongation common to 

 the bases of tlie posterior teeth, the last two or tlu'ce 

 being set on a jirocess jutting from the pharyngeal 

 bone into tlie [jharynx. The heart-shaped jiharyngeal 

 cartilage of the three preceding species is modified here, 

 this organ being elongated into a tongue-like form, with 

 the anterior (upper) end obtusely rounded, and the 

 posterior, tapering extremity only slightly folded and 

 elevated, scarcely marked off from the other part. 



The dorsal tin, which is particularly remarkable 

 for its height, is oblicpiely truncate at tlie margin, with 

 pointed corners, especially behind. It begins at a di- 

 stance from the tip of the snout that increases with 

 age and measui-es about 44' ^ — 48',;, % of the length 

 of the body, or half the length to the base of tlie caudal 

 tin. 'fhis distance is on an average less tiian in any 

 of the three preceding species. In this respect the Koach 

 comes nearest to the Cyprinine group; and the other 

 Leuciscines have evidently followed a special direction 

 of development from that group, reaching different 

 stages. The Dace has advanced furthest, as shown by 

 the table gi\en below". The base of the dorsal fin 

 measures about 14 — Ti %, its height about 20' ., — 17 

 %, of the length of tlie body. The anal tin. tlie di- 

 stance between whicii and the tip of the snout is about 

 63 — 68 ?o of the length of the body, resembles in form 

 that of tlie Ide. The length of its base is about 12 — 

 10' , %, its height about 13' „— 10',,. %, of the length 

 of the bod\'. The caudal tin is rather deeply forked. 



it.s middle rays occupjing about 9 — 8 % of the length 

 of the body and measuring about .''(i — 4(t % of that ot 

 the longest caudal ra\.s. 



The pectoivil and \eiilral litis lia\f the same form 

 as in the Ide. but differ only slightly in length, that 

 of the former \arying between about 17 and 14' „ %. 

 Ih.it of the latter between 17 and 14 %, of the length 

 of the bod\-. The distance between the \-entral fins and 

 the tip of the snout measui'cs about 4;) — 47 ?«/, the pre- 

 abdoniinal length about '2i — 2.5 %, and the postabdo- 

 minal length about 2U — 22 %, of the length of the body. 



The scales resendde those of the three preceding s]>e- 

 cies, but are com])arati\el\' niueh larger than the Ide's, 

 and as a rule larger even tlian the ("hull's, a point which 

 is shown b\- the abo\e estimates tif their number in the 

 lateral line and in a transverse row between the dorsal 

 and ventral fins. During the spawning-season they arc 

 destitute of the rim then present round the scales of 

 the Ide, but are strewn in the mali' with the usual, 

 pointed, \errucose tnbeirles. 



The sexes are distinguished only by tlie more 

 slender body of the male and the said spiniferous tu- 

 bercles, whicli are scattered during the spawning-.season 

 on the skin of tiie head, the opercula, the scales co- 

 vering the forepart of the body, and the first ray of 

 the pectoral tins. According to a note on v. Wright's 

 original, our figure represents a male without this ex- 

 ternal sexual character. 



The up])ei- part of the head and back is of a dark, 

 blackish given, which rapidly passes below into brighter 

 green, and then gradualh' into the lustrous silvery gray 

 of the sides, which at the middle are faintly tinged 

 with bronze and towards the belly shade into yelUnv. 

 Each of the scales is marked at the base with a green- 

 ish spot, darker on the u])iierinost scales, gradually fad- 

 ing and at last disappearing on the lower ones. In the 

 lateral line the scales are furnished with two similar, 

 but smaller spots, lying one on each side of the dnct. 

 which is yellowish. In some specimens the iris is of 



