416 THK HERRING FAMILY. 



appearance of the young fish may be seen in Plate XIX, fig. 5. 

 The chief differences from the last stage are the alteration in 

 shape of the body owing to greater increase in breadth and the 

 increase of black pigment. The former causes the young fish 

 to resemble the adult more closely in its proportionate dimen- 

 sions. The position of the vent is further forward and the anal 

 fin has appeared. The ventral fins arise as a pair of folds about 

 half way between the vent and the gill-slits. The black 

 chromatophores in the wall of the abdominal cavity have 

 increased and further continue to do so, although the growing 

 opacity of the body- wall gradually hides them from view. The 

 row of black dots below the intestine may now be seen, not only 

 under the posterior half of this organ but anteriorly as well. 

 Finer black pigment-spots cover the general surface of the body, 

 especially dorsally, arid on the tail. The tip of the notochord 

 is bent up dorsally at its caudal end, and the eyes are very 

 large and conspicuous. 



Shortly after this the silvery sheen of the adult commences 

 to appear, especially on the head and lateral line, and the young 

 herring reaches the ' whitebait' stage. Although at one time 

 the ' whitebait' (Clupea alba) was claimed by some naturalists 

 as being specifically distinct from the other clupeoids, there 

 can now be no doubt that it is the young stage, in the majority 

 of cases, of the herring and in a few cases of the sprat. The 

 proportion belonging to each of these species in any given 

 'haul' depends largely upon the locality and the season. 



Pennant, as early as 1776, examined the whitebait of the 

 Thames and declared them to be neither young shad, sprats nor 

 smelts, but was inclined to consider them to be the fry of the bleak. 

 Donovan later examined some whitebait and considered them 

 to be the young of the shad, and later still Yarrell contradicted 

 the results of both his predecessors. He claimed for whitebait 

 a separate species and named it Clupea alba, the whitebait 

 representing mature individuals. Cuvier states that the white- 

 bait (C. alba.) frequent brackish water to mature their spawn. 

 This was carried still further by Valenciennes, who actually 

 attempted to found a fresh genus (Rogenia) for these little 

 fishes. Subsequent investigators have not been able to confirm 



