72 TWAITE SHAD. 



the purpose of spawning; on which account this fish, as well as the Allis Shad, is on the 

 Continent sometimes called "May-fish;" it remains in our rivers for two or three months, 

 and then descends to the sea. These fish were formerly very abundant in the Thames. 

 Yarrell says that Twaite Shads appear during the months of May, June, and July, in great 

 numbers in the Thames from the first point of land below Greenwich, opposite to the Isle 

 of Dogs, to the distance of a mile below, and that many are taken, but that they bring a 

 small price to the fishermen, being in litde repute as food, "their muscles being dry and full 

 of bones." The present condition of the Thames, I suspect, prevents this periodic migration 

 of the Twaite Shad. 



Some writers have supposed that the Twaite can be distinguished from the Allis by its 

 possessing teeth in both jaws, and by having a row of dusky spots along each side of the 

 body, the Allis having one spot only near the head ; but Dr. Giinther has shown that it is 

 impossible to form "a systematic arrangement of a group of animals based exclusively on 

 differences in an organ which has become rudimentary, or where it is subject to even 

 individual variations." The teeth in the members of the genus Clupca are a ver}' unsafe 

 guide whereby to lead to real characteristic distinctions; "they are more or less completely 

 lost in a number of individuals either by accident or by age ; those on the tongue, if 

 present, are a more constant part of the dentition ; yet there are numerous species in which 

 the lingual teeth are few in number, and as readily lost as those in the jaws. Nearl)^ the 

 same may be said with regard to the teeth on the palate ; and innumerable instances mav 

 be met with in which it is impossible to say whether a certain bone has been provided 

 with teeth or not." In the two Shads there is no real difference in the dentition ; neither 

 species has teeth on the palate, the vomer, the tongue, or on the under jaw, while the teeth 

 on the intermaxillary and the maxillary (upper jaw) are deciduous. Both species are occa- 

 sionally marked with a series of blackish patches along the sides of the body ; in the 

 discrimination, therefore, of these two Shads, recourse must be had to the examination of 

 the gill-rakers as the only safe guide. 



What the derivation of the terms Shad, and Thwaite or Twaite ma}' be, I know not ; 

 the specific name o{ Jinta is the Italian finta, "simulation." The French name of this Shad 

 is La Fcinte, and doubtless, as Littre says, was given to this species because it resembles the 

 Allis Shad; '■'■ Ainsi dit parce que c' est tine alose feintc.'''' The Germans generally call the Allis 

 Shad Die MaifiscJi, or Aluffcrhanrig, and the Twaite Shad Die Finte. 



There is no real difference in the fin rays of this species from the other Shad. 



