LEUCI8CU.S FRIESII. 155 



ventral and anal fins are bluisli-white at their bases, sometimes becoming 

 reddish. At spawning-time the males develop remarkably large conical 

 pointed tubercles, vs^hieh grow from rounded bases, like the tubercles of 

 Leuciscns pi(jus. The white colour of these thorn-like processes has suggested 

 the name of Perlfisch for this species. The largest tubercles are found 

 on the upper part of the head (Fig. 80) and fore part of the back; the 

 smallest on the fins. When this growth takes place the entire abdomen 

 acquires a delicate red colour. 



The Perlfisch grows to a larger size than the Nerfling, measuring over 

 twenty inches when adult, and Von Siebold mentions some examples which 

 measured twenty-six inches ; the weight may be about ten pounds. 



It commonly lives in deep water during the whole year, and in the lakes 

 comes to the surface only at spawning-time, in tlie *first half of May, 

 when it may ascend the tributary brooks. It then feeds on earthworms, 

 cockchafers, and small fishes. During the spawning-time — which, according 

 to Von Siebold, lasts a fortnight, and, according to Heckel, three weeks — 

 the Perlfisch are chiefly caught with the line, and then are t) be seen in the 

 Munich fish market, though not much valued for food. In lakes the young 

 fishes commonly live at a depth of fifteen fathoms, but the oldest may be taken 

 in six fathoms. 



The skeleton, according to Gilnther, consists of twenty-six vertebrae in 

 the dorsal region and seventeen in the tail, which is one fewer in the back 

 and two more in the tail than in L. pigas. The pharyngeal teeth are 

 powerfully developed ; they are in a single row, six on one side and five 

 on the other ; they are club-shaped, owing to a constriction towards the 

 base ; and the teeth are described by Von Siebold as more compressed than 

 in the Nerfling. 



Leuciscus cephalus (Linn^us). — The Chub. 



D. 11, A. 11—12, V. 10, P. 14—15, C. 10. 

 Scales : lat. line 42—16, trans. 7A/6i. 



The Chub (Fig. 82), which is widely spread over Europe and Asia Minor, 

 belongs to the division of the genus Leuciscus in which the pharyngeal teeth 

 are in two rows, a type which most Continental writers regard as of generic 

 importance, and as forming their genus Scpialius. 



The body is thick, but slightly compressed, with a very broad head. The 

 body is more than five times the length of the head ; the greatest thickness 

 is less than half the heiirht. The head is lono-er than hi^h, and the 



