584 TELEOSTEI CHAP. 
travelling long distances, against rapids and over waterfalls, to 
reach their breeding places at the heads of rivers. During the 
breeding season, the males of many species assume a more 
brilliant livery, or develop pearl-like or spiny excrescences on 
various parts of the head, or also on the body and fins.t Cyprinids 
are oviparous, with the exception of a small Barbel from Natal, dis- 
covered and described by Prof. Max Weber as Barbus viviparus. 
A most striking instance of symbiosis is offered by a little 
Carp-like fish of Central Europe, the “ Bitterling” (Ahodeus 
amarus).  The* genital papilla of the female acquires a great 
development during the breeding season, becoming produced into 
a tube nearly as long as the fish itself; by means of this ovi- 
positor the comparatively few and remarkably large eggs, measur- 
ing 3 millimetres in diameter—the fish being only 60 to 80 
millimetres long—are introduced through the gaping valves, 
between the branchial laminae of pond mussels (Unio and 
Anodonta) where, after being inseminated, they undergo their 
development, the fry leaving their host about a month later, 
having attained a length of 10 or 11 millimetres.” The molluse 
reciprocates by throwing off its embryos on the parent fish, in 
the skin of which they remain encysted for some time, the 
period of reproduction of the fish and mussel coinciding. 
Some members of this family grow to a very large size,—4 to 
6 feet; such is the case with the Carp, a native of Asia, intro- 
duced into England towards the beginning of the seventeenth 
century ; the Catla (Catla buchanan?) of India, Burma, and Siam ; 
the Mahaseer (Barbus mosa/l) of the mountain streams of Asia, 
the scales of which may be as large as the palm of a hand; and 
Hypophthalmichthys molitriz of China and Manchuria, remark- 
able for the low position of the eyes, the fusion of the gill-rakers 
into thin plates of spongious appearance, which must act as a 
most efficient sifting apparatus, and the presence of an involuted 
problematic superbranchial organ to each branchial arch.? 
Among well-known aberrations produced by artificial selection 
may be mentioned the “Leather Carp,” a race in which the 
scales are either lost or much reduced in number, and enlarged 
1 Cf. Baudelot, Ann. Sci. Nat. (5), vii. 1867, p. 339, and Leydig, ‘‘ Unters. 
Anat. u. Histol. d. Thiere” (1885). 
° Cf. Noll, Zool. Gart. 1869, p. 257, and 1877, p. 351; Olt, Zettschr. wiss. Zool. 
lv. 1893, p. 543 ; Cuénot, Bull. Soc. Zool. France, 1898, p. 53. 
* Boulenger, Ann. and Mag. Nat. Hist. (7), viii. 1901, p. 186. 
