388 Vertehrata. 



carpio), with foui- barbules on the upper edge of the mouth (introduced from Asia) : 

 the Prussian Oarp (Carasaius vulgcms), without barbules, but otherwise 

 similar: the Gold-fish (Car. auratus), from China: the Barbel (Barhus 

 vulgaris), with four barbules, of which two are at the tip of the snout : the small 

 Gudgeon {Gdbio fiuviatilis) : the Roach (Leucisus) : the Tench (Tinea 

 vulgaHs), with small scales in a thick slimy skin: the small Bitterling 

 (Rhodeus amarus), females provided at spawning-time with a long ovipositor 

 bearing the genital pore at the tip, by means of which the eggs are laid in the 

 branchial chambers of the Freshwater Mussels (Draio) : the Bream (Abrainis 

 bramia), with high, laterally compressed body: the Loach (Gohitis), small fish 

 vrith elongate, sometimes eel-Uke, bodies ; very small scales concealed beneath the 

 skin ; six or more barbules, intestinal respiration (see p. 375). AU these, except the 

 Gold-fish and the Bitterling, are indigenous to the British Isles. 



5. The SiluruB family (Siluridse). The body never has the ordinary 

 scales ; it is either naked, or provided with large bony plates (dermal denticles 

 may be present) ; maxiUse very poorly developed ; barbules and an adipose fin 

 usually present. Freshwater Fish, which are represented by numerous intei-esting 

 tropical forms. The Sheat-fish (Silurus glanis), naked, with quite small 

 dorsal fin far forward, long anal fin, two long and four short barbules, small 

 eyes; as much as 4 m. long; the only Eiiropean representative of the family, 

 occurs in England. The electric Silurid (Malapterurus electricws), with adipose 

 fin (but otherwise without a dorsal fin), more than 1 m. long, in Africa. The 

 Loriearia, skin covered with large bony plates, in S. America. 



6. The Eel family (Mursenidse). Body snake-like, smooth or with small 

 scales ; without pelvic fins ; dorsal, caudal, and anal fins continuous ; small gill- 

 slits ; small eyes. The Eel (Anguilla vulgaris), with scales ; spawns in the sea, 

 probably in deep water ; the young, whilst still transparent, wander into fresh 

 water, returning to the sea later. The Conger-eel (Conger vulgaris), scale- 

 less, attains a considerable size (2 m.) ; in the North Sea. The M u r sb n a 

 (Gymnothorax murxna), apodous, even the pectoral fins being absent; in the 

 Mediten-anean. To another family of snake-like Physostomi belongs the 

 Electric Eel (Gymnotus electricus), of S. America; anus close to the head; 

 anal fin long ; no dorsal and pelvic fins ; the large electric organs along the 

 ventral side reaching to the tip of the tail. 



Sub-Order 2. Aphysostomi. 



No pneumatic duct. Pelvic fins, generally moved far forw^ards. 

 Spinose rays usually present (not in sub-divisions^ 1 — 3). 



1. Mackrel-pikes (Scomberesocidse). Cycloid scales; dorsal fin short, 

 far back; pelvic fins far back; no spinose rays. The Gar-pike 

 (Belone vulgaris) has mandible and premaxilla elongated to form a beak, beset 

 with fine teeth; body elongate; bones green; in the North and Baltic Seas. 

 The Flying-fish (Exocoetus) distinguished by the enormous development 

 of the pectoral fins, by means of which it can take short flights across the 

 surface of the ocean ; in tropical seas (one species in the Mediterranean). 



2. The Cod-fish family (Gadidx). Body somewhat elongate with 

 small cycloid scales ; usually two or three dorsal, and one or two anal fins ; 

 pelvic in front of the pectoral-fin, no spinose rays; often a barbvde on the 

 lower jaw. To the genus Gadus, with three dorsal and two anal fins, 

 belong: the Codfish (G. morrhua), which occurs in immense shoals in the 

 North Atlantic, up to 1.5 m. in length ; the Haddock (G. xglejvnus), numerous, 

 e.g., in the North Sea; both these have barbules: the Eel -pout (Lota 



