ill fVdiit tiiw.'irds tlic siKiut. Tliis (loju-cssidii is most 

 (li-itiiirt ill ciid s|ieciiiicns, in which tiic cxtci'iialh' li;ire 

 hind jiMrts lA' (he tVoiital liiiiics too are more distiiictiy 

 inari<ed witii I'adiatiiig stria'. The eyes are rouiul (with 

 the lon^ntudinal diaiiietei' slightly <TreMter than the xcr- 

 tical) Mild aiT set rather hii;li, li\ l';ir the lii'catcr paii 

 of them Iviiiu' al)(i\(' a liorizonlal line tVuiii the tiji ol' 

 the simnt lo the middle of the eaiidal tin. In speci- 

 nieiis Ijetweeii '■'> and ') dm. long their longitudinal dia- 

 meter measures aliout 15 — 14 % of the length of tlie 

 head: in Aduiiger ('arp thc\- are as usual e<ini|iarati\'(>i\' 

 larger, their longitudinal diameter, when tlie h(id\- is 

 i dm. long, being ahmit ' . of the length of tlie head, 

 wiien the body is ' 4 dm. long, about ' 4 of the same. 

 The nasal eavities lie just in front of the upper an- 

 terior eorners of the orbits. Tlie two nostrils on each 

 side are fairh" large and round, the diameter of the 

 posterior iieing about e([ual to its distance from the 

 orbit. The\' are set close to each other, tiie anterior 

 obliquely on tlie inner side of the posterior; and the 

 margin of the anterior nostril is raised liehind in an 

 obli(|uelv cut, canaliculate form, so as to compose a 

 lid with which the aperture may be closed. The distance 

 between the two anterior nostrils is somewhat less than 

 their distance from the middle of the tip of the snout, 

 but about e(|ual to half the breadth of the intcrorbital 

 space above the centre of the eyes. The length of the 

 snout varies, hoAvever, quite considerably, from '3 of 

 the length of the head in ^•oung Carp t(^ about o" % 

 thereof in old. The mouth is fully terminal, the cleft, 

 when the mouth is closed, slightly ascending, and the 

 gape, when protruded and wide open, of a rounded 

 quadrangular form. The lips are fleshv: the upper li]) 

 is double, the maxillary lione being also furnished with 

 a dermal fold, in which tiie two pairs of barbels have 

 their origin; the lower lip hangs down along the sides 

 of the lower jaw in front of the corners of the mouth. 

 The barbels are flattened at the base and vary con- 

 siderab]\- in length; the lower (at the corners of the 

 mouth) may be half as long again, according to Fatio, 

 as the diameter of the eye, but are usually shorter and 

 in young Carp nuich shorter than the diameter of the 

 eye; the U]i]ier (anterior), which are set about iialf wa\- 

 along the maxillary bones or a little higher, are only 

 half or one-third as long as the lower; but we nuist 

 not forget that during life these barbels are capable of 

 extension and contraction. The length of the uiijier 

 jaw, measured from the nuddle of tlie tip of the snoiit 



to the hind e\treniit\' of the maxillary bones, is in 

 adult Cai'p about 27 or 28 ?i, and the length of the 

 lower jaw .31 — 3() ?6 of the length of the head. The 

 gill-openings extend from the upper posterior corner 

 of the o])crculum to the isthmus, about to the perpen- 

 dicular Iroin the artieular knob (njijier anterior corner) 

 ol (he operculum. The branchiostegal membranes are 

 below united to the isthmus at a. distance from each 

 other which in old specimens is equal to the longi- 

 tudinal diameter of the eyes. The branchiostegal ra^•s 

 are ."> in niimbiM', in accordance with the general rule 

 within the faniih-; but l-"A'iin on one occasion funn<l I 

 rays in each meinbrane. The ojierculum is obliipieh' 

 quadrangular (rhomboidal), with the lower posterior 

 angle rounded and obtuse. The anterior margin is the 

 longest, Ijeing abt)ut ecpial in length t(j the postorbital 

 ]iart of the head, or to about half the entire length of 

 the head. The hjwer margin is slighth' indented in a yer\' 

 elongated S-shape or even straight. The surface of the 

 operculum is striated Ijy granulated ridges with inter- 

 jacent grooves, radiating backwards and downwards from 

 the artieular knob. The crescent-shaped suboperculum, 

 which coasts the inferior margin of the operculum, is 

 distinctly (about '/j) longer than the lower jaw. The 

 triangular interoperculum, pointed at the top, tills the 

 angle between the two bones just mentioned ;\nd the 

 lower part of the preopereulum, and coasts the inside 

 of the hoi'izontal (lower) arm of this last bone forward 

 to the point of union with the articulation of the lower 

 jaw. The hind angle of the preopereulum is obtuse 

 and rounded. The cheeks are soft; but the space be- 

 t^veen the eye and the u]3i)ermost part of the preoper- 

 eulum is filled by the posterior bones of the orbital 

 ring. The sul)orliital liones are also thick and tirm, 

 striated like the operculum. The gill-rakers are short 

 and rather scattered (18 — 2(1 in the outer row on the 

 first branchial arch), consisting of pointed triangular 

 disks \vith dermal papilhe on the inner margin. The 

 lower piharyngeals (fig. 178), the mucous membrant' of 

 which is fringed at the outer superior margin with 

 similar, but smaller gill-rakers, 22 in number, are fur- 

 nished within this margin as a rule with five teeth each; 

 but while the teeth are being shed, one or two of these 

 mnx be wanting or may lie hidden or loose in the 

 nuicous mendjrane. The largest teeth are 3 in number, 

 set in an inner row. The first of them is bluntly conical, 

 with a greater or less degree of lateral compression, 

 and never shows sisns of wear by grinding, l>ut bears at 



