368 THE FRESH-WATER FISHES OF EUROPE. 



The cephalic canals are distinct, and are traced by their pores along the 

 pre-operculum round the eyes and on the lower jaw. The bony elements of 

 the sub-orbital ring are strongly developed. 



The large stomach extends back in the abdominal cavity to the ventral fins, 

 and is surrounded by the moderately large liver. The liver opens by a wide 

 duct into the pyloric region. The intestine is slender, and makes a forward 

 curve under the liver, and then curving again, passes into the large intestine, 

 which runs straight to the vent. The air-bladder extends the entire length 

 of the abdominal cavity, and opens by a short pneumatic canal into the lower 

 and hinder wall of the gullet. The ovaries of the female form long sacs, which 

 are small in front and covered with black pigment ; the eggs are small. The 

 kidneys are small in front and expand in the region of the vent to thick 

 glandular masses. The small long urinary bladder and the oviduct open 

 behind the vent. The male has in this region a projecting papilla. 



The colour is reddish-brown, becoming blackish-brown on the back, and 

 paler on the belly. The lateral line is indicated by a pale-yellow or copper-red 

 line. The head and body are spotted and dotted irregularly with dark-brown 

 pigment. The dorsal and caudal fins are brownish, the former has some spots ; 

 the other fins are pale. The male sometimes has a red line along the middle of 

 the belly from the throat to the vent. 



Males are rarer than females, and have a more elongated body. They 

 are smaller fishes, often scarcely two inches long, while the females measure 

 three inches, or three inches and a half. 



This Ilundsfisch lives in company with the River Bullhead, Crucian Carp, 

 and Roach, in the marshes adjoining the Hungarian lakes, but it prefers 

 muddy bottoms of deep pools. It is rare for more than five or six to be taken 

 at a time, as it is shy, active, and buries itself in the mud. 



When swimming, the pectoral and ventral fins move alternately like the 

 feet of a dog in running, and the dorsal fin at the same time moves with a 

 wave-like motion like that seen in the Sea-horse tribe, Hippocampus and 

 Syngnathus. This condition is apparently due to the muscles which are 

 attached to the individual rays being capable of independent action. Even 

 when the fish is otherwise still, the last three or four rays of the dorsal fin 

 oscillate as in Hippocampus. The animal is sometimes at rest in a horizontal, 

 sometimes in a vertical position, and may remain for hours together with the 

 head directed either upward or downward, then with a sudden rapid movement 

 of the tail it comes from deep water to the surface and swallows air, which is 

 ejected in large bubbles through the gill-openings, and it then breathes slowly 

 for some time. Heckel and Kner kept this fish in captivity for a year and a 

 half, and fed it with small pieces of raw meat, which were never touched till 



