56. LEuciscus. 235 



rence in rapid streams, — which characters indicate at once the nature 

 of the hsh described by Pallas. Heckel and Bleeker, guided by the 

 accidental circumstance that the anal is said to be 23-rayed, referred 

 the fish to Ahramis. However, this number is evidently a misprint 

 for 13, inasmuch as Pallas enumerates, in his section d, ftrst the 

 species with short anal fin (and among them is C. clinjsojjraslus), 

 then those with that fin elongate, and finally those with very long 

 anal. — Some other authors have referred this C. chrysopraslus to 

 Leticiscus phoodnus. 



Hybrid between Leuciscus muticellus and Chondrostoma nasus. 



Chondrostoma 7-i/sela, Agassiz, Mom. Soc. Sc. Nat. Neuchatel, i. 

 1835, p. 3S ; or Wiegm. Arch. 1838, p. 80 ; Heckel, Sitzgsber. Akad. 

 Wiss. Wien, ix. 1.^52, p. 377, taf. 8 ; Heckel & Kner, Siisswasserf. 

 p. 220 (C'hondrosto)na r/enei, part.); Siebold, Siisswasserf. p. 232. 

 tig. 42, is, according to the researches of Siebold, a hybrid between 

 Chondrostoma nasus and Leuciscus muticellus. Externally it re- 

 sembles sometimes more the former, at other times the latter. 

 The cleft of the mouth is always more arched than in Ch. nasus. — 

 Pharyngeals generally 5 . 6, sometimes with an additional odd 

 tooth in a separate series. The pharyngeal bones have generally a 

 shallow notch on their extero-anterior margin. D. 11-12. A. 12- 

 13. L. lat. 50-60. L. transv. ||. 



29. Leuciscus uMiva. 



Squalius ukliva, Heckel, in Eusscggers Reisen, i. p. 1042 ; Heck. Sf 

 Kner, Siisswasserf. p. l99. fig. 112. 



D. 10-11. A. 11-12. L. lat. 62-65. L. transv. 11/9. 



The height of the body is rather more than one-fourth of the 

 total length ( without caudal). The width of the interorbital space 

 is more than the diameter of the eye, and about one-third of the 

 length of the head. The cleft of the mouth docs not quite reach 

 the vertical from the front margin of the eye. Snout convex, the 

 upper jaw overlapping the lower. Origin of the dorsal fin opposite 

 to the middle of the base of the ventral. There are five longitudinal 

 scries of scales between the lateral line and ventral fin. A more or 

 less distinct dark band along the side of the head and body, above 

 the lateral line ; base of all the fins orange-coloured. Pharj-ngcal 

 teeth 5 . 2—2 . 4 or 5 ?. 



River Cettina (Dalmatia). 



Or-b. Adult. Elver Cettina. From the Milan Museum. 



The following example is evidently a hi/hr!d between L. ukliva 

 and Alburnus alhurnellus. It has A. 1(! and L. lat. 44, but the 

 scales are striated, and there is a dark band along the side ; base of 

 the fins orange-coloured. 

 a. Four inches long. Piiver Xarenta. From the Milan Mu>eum. 



