140 Mr. Yarrell on Whitebait and Shad. 



investigation, which I have pursued to the present time. I am aware it 

 may be urged, that the periodical visits of fishes as well as other animals are 

 influenced and varied by the temperature of particular seasons and the 

 condition of the animal, but as all the comparative observations I shall 

 make on this subject will be confined to the fish of the same river, and 

 during the same season, this objection will not be valid. Whitebait con- 

 tinued to be procured in the month of April ; more abundantly through- 

 out May as the weather became warmer; and with the exception of 

 occasional interruptions to the fishing, from the activity of the Water 

 Bailiff and his deputies, the taverns at Greenvnch and Blackwall, as well 

 as several fishmongers in London, have continued to receive a supply up 

 to the present time. The same arrangement that produced me the Shads, 

 produced me also constant supplies of small quantities of Whitebait for 

 weekly examination, and the additional fee which I had promised the 

 fishermen for every young Shad that was preserved for me, produced me, 

 as I have reason to believe, every young fish of that species, as well as 

 any portion I pleased of other fishes, neither Whitebait nor Shads, which 

 the parties I engaged with caught in the pursuit of their avocation. The 

 number of young Shads however did not exceed a score, nor did I obtain 

 one till the end of June, recogniseable instantly from the Whitebait, and 

 both species distinctly known to the fishermen. I may here also add, 

 that no Whitebait are found in other rivers frequented by the Shad ; not 

 a single example of Whitebait is ever taken between Putney and Ham- 

 mersmith, where the Shads deposit their spawn; and although Shads 

 abound in the Severn, which affords this fish in higher perfection than 

 any other river, particularly near Gloucester where immense quantities 

 are taken, the Whitebait are unknovm ; nor do I ever remember to have 

 seen a notice of the appearance of this fish in any other river in England 

 except the Thames. 



But it is not alone on such data as these, however conclusive they may 

 appear, that I rely, for the distinction for which I contend. The best 

 Zoologists of the last fifty years have taught us the value as well as the 

 necessity of searching for, and resorting to anatomical distinctions, as the 

 best foundation for the separation of species, and I shall therefore proceed 

 to detail the various differences that present themselves on a close ex- 

 .amination of the external and internal characters cf the Whitebait and 



