31. CYPRINIDJi: SQUALIUS. 
231 
booked, with narrow grinding’ surface or none. (Grinding surface 
present in Squalius leuciscus, obsolete in most of our species.) Anal 
basis short or somewhat elongate. Dorsal lin posterior, usually behind 
V’entrals. Intestinal canal short. Size generally large. A very large 
group, one of the largest current genera in ichthyology, represented by 
numerous species in the rivers of Europe, Asia, and Xorth America. 
Most of our species have been poorly delined. The majority of Girard’s 
original types have been preserved, and the descriptions here given are 
mainly taken from them. Much larger series of each form are neces- 
sary before the species can be properly discriminated. Individual irreg- 
ularities in dentition are common in this genus. (From squalus, a 
shark; some early writers on ichthyology having called the typical spe- 
cies Squahis minor, for no evident reason.) 
The species may be divided as follows : 
* Teeth normally without grinding surface. 
t Caudal peduncle not very stout, its least dei)th not two-thii’ds the length of the 
head. 
t Mouth very wide, the lower jaw much projecting beyond upper, the upper lip 
on the level of the middle of the pupil, and the maxillary reaching to be- 
low the pupil ; body elongate, compressed ; dorsal well backward (Cli- 
XOSTOMUS Grd.) elongatus, vandoisulus, estor, funduloides. 
It Mouth moderate or small, terminal, oblique, the lower jaw little projecting, 
premaxillary below the level of the pupil, and the maxillary not reaching 
to the pupil. (Tigoma Grd.) 
a. Anal basis elongate, its rays 10-12 hijdroplilox, tcenia, montanus, liumboldti. 
aa. Anal basis short, its rays 8 or 9. 
b. Scales in lateral line 50-G5. 
cnioreus, ardesiacus, pandora, margaritus, gula, piulcher, 
egregius, lineatui, gracilis, conformis, bicolor, obesus, purpureus. 
bb. Scales in lateral line 6r)-80. 
pulclicllus, intermedius, alicicc, copci, niger, consjyersus. 
tt Caudal peduncle very deep and compressed, its least depth nearly equal to the 
greatest depth of the he.ad ; dorsal over ventrals ; scales rather large 
(SiBO.^iA Girard) gibbosus. 
** Teeth with evident grinding surface. (Squalius.) 
c. Robust .species, the depth 3-0^ in length ; lateral line less than 60. 
rhomaleus, sqiiamatus, atrarius, crassus. 
cc. Slender species, the depth 4-4J in length; lateral line 60-70 (Cheoxda 
Grd.) cocruleus, cooperi, nigrescens, modestus. 
* Teeth (normally) without grinding surface (various irregularities often present, so 
that the character has little value). 
t Caudal peduncle not very stout, its least depth not two-thirds the length of the 
head. 
t Mouth very wide, the lower jaw much projecting beyond upper, the upper 
lip on the level of the middle of the pupil, and the maxillary reach- 
ing to below the pupil ; body elongate, compressed ; dorsal well back. 
{Clinostomus Girard.*) 
* Girard, Proc. Acad. Nat. Sci. Phila. 1856, 211; type Luxilus elongatus Kirtland 
{hXivoo, to incline; Ozojua, mouth.) 
