ENTOMOSTRACA FROM THE GULF OP ST. LAWRENCE. 51 



Oithona similis, Claus. — This species occurred very sparingly 

 in one of the gatherings mentioned above, along with Tortanus 

 discaudatus. It is a widely distributed species, and is some- 

 times frequent in the British seas, where it is usually referred 

 to under the name of Oithona spinifrons, and sometimes 

 0. helgolandica, Claus. Oithona similis is recorded by Dr. 

 Giesbrecht in his Report on the Copepoda obtained in the col- 

 lections brought from the Antarctic by the German Expedition 

 in the steam yacht " Belgica." The same author has also 

 recorded the species from the Mediterranean and from Kiel. 



Argulus alosce, Gould.* — A single somewhat immature specimen 

 of this Argulus was obtained in a small sample of Copepoda 

 collected off Griffins Cove in 1872. This specimen, though not 

 full grown, possesses the more important characteristics by 

 which A. alosce is distinguished, and I have no hesitation in 

 ascribing it to that species. The specimen measures fully four 

 millimetres in length, but the length of one full grown is, 

 according to Wilson's description, seven and a-half millimetres. 



The species appears to be confined to the coasts of North 

 America, and is found on several kinds of fishes, but that on 

 which it was first discovered by Dr. T. W. Harris is called the 

 Ale Wife, Clupea vernalis, Mitchell (Pomolochus pseudoharengus, 

 Wilson). Gould, who first described the Argulus alosce, con- 

 sidered the Clupea vernalis to be identical with the European 

 Clupea vulgaris, Cuv. (C. alosa, Lin.), better known to us by the 

 name of Allis Shad ; but Mr. C. B. Wilson, whose work is referred 

 to above, and from which the information given here is chiefliy 

 obtained, says that this fish does not occur on the American 

 coast, while the Ale Wife is quite common, and from it have 

 been obtained most of the recent specimens of the Argulus 

 alosce. It may, however, be of interest to mention that, accord- 

 ing to Day's British Fishes, Vol. I., page 235, "Ale Wife" is 

 one of the names used by the Welsh fishermen to designate 

 both the Allis (or Allice) and the Twaite Shads. 



Mr. J. F. Whiteaves reports the occurrence of an Argulus 



* 1841. Argulus alosae, Gould, Invertebrata of Massaehiitetts, p. 340. 

 1902. Argulus alosa, C. B. Wilson, " North American Parasitic Cope- 

 poda of the family Argulidae," Proc. U.S.A. National Miw., Vol. XXV., 

 p. 797, PI. XII. ; PI. XXVI., fig. 80. 



