128 THE FRESH-WATER FISHES OF EUROPE. 



the ventral cavity. The air-bladder, as in other Cyprinoids, is divided trans- 

 versely. There is a round and short anterior part, and a posterior part which 

 ends in a blind point, and is provided with an air-canal. Under the termina- 

 tion of the air-bladder, the lobes of the ovary or milt unite in a common duct, 

 by which their ripened elements are discharged. There is a small pear-shaped 

 urinary bladder. The milt and ovaries are symmetrical and double; the 

 ovaries are closed sacs, which run the whole length of the ventral cavity and get 

 smaller behind as they join in the common urogenital canal. The milt lobes 

 are much less developed, and do not extend far into the ventral cavity, but 

 their small glandular lobes similarly unite in the outlet of the bladder to form 



a common urethro-genital opening. In the male 



the abdominal skin is coloured with a black 



pigment. 



The size is variable ; the largest known females 



are five inches long. 

 Fig. 55.-PHARYNGEAL TEETH OF r^ figh was firgt discovered by Heckel in 



AULOPYGE HUGELII. 



1840, in the fish markets of Dalmatia. Its habits 



are entirely unknown, and Heck el records it only from the brooks and rivers 

 of Dalmatia and Bosnia. 



It is eaten in Bosnia cooked in oil, and is stated to be well flavoured. 



GENUS: Gobio (CuviER). 



The Gudgeons are a small genus, closely allied to the Barbels, and limited 

 to Europe. The dorsal fin has no spine. The jaws are equal in length. 

 Both have simple lips, and there is a well-defined barbel at the angle of the 

 mouth. The pharyngeal teeth are in two rows : five in the principal row, and 

 two or three in the secondary. They are hooked at their extremities. The 

 gill-rakers are very short. 



Gobio fluviatilis (RONDEL). The Gudgeon. 



above 6| 



D. 3/7, A. 3/6, V. 2/78, P. 1/1415, C. 19. Scales : lat. line 4044. 



below 6 



The body of the Gudgeon (Fig. 56) is four and a half times as long as high, 

 and a third higher than wide. The head is more than one-quarter of the length 

 of the body ; the eye, which is near the top of the head, is about one-fifth of 



