M. T. Thorell on the Species of the Argulidse. 439 



locomotion ainsi que Fabdomen etant en trop mauvais etat pour 

 que je puisse en decrire la forme, je n'en parlerai pas." By the 

 word bee is probably meant the sting, not the mouth-tube. All 

 further information respecting this animal is summed up as 

 follows : — " Cetteespece est bien moins discoidale qncV A. folia- 

 ceus .... Jaunatre, la tete est grande, tres-allongee, et parait 

 arrondie h ses parties anterieure et posterieure; elle est forte- 

 ment sillonnee longitudinalement entrc les yeux, et ceux-ci, qui 

 sont noirs, affectent une forme discoidale. Le test est tres-dilate^ 

 membraneux, transparent et parait posterieurement ne pas etre 

 depasse par V abdomen ; il est jaune, finement pointille de rou- 

 geatre, et parcouru longitudinalement, de chaque cote, par une 

 ligne d'un brun rougeatre." 



Of more value than this description is the statement that the 

 animal was procured " en mai sur une Raie qui avait ete prise 

 dans la rade d'Alger, entre le fort de I'Eau et le cap Matifou." 



The figure gives no clearer idea of the characters of the animal 

 than the description. I have placed it next to A. purpureus on 

 the ground of the elongated form of the shield, and because, as 

 would seem to be expressed above, it appears to stretch over and 

 cover the tail, as in that species. Both occur, moreover, in the 

 same sea. 



3. A. foliaceus (Linn.). 



Syn. Monoculus foliaceus, Linne, Syst. Nat. ed. 10, torn. i. (1758) p. 634. 

 Arrjulus Charon, Miiller, Entomostraca, (1785) p. 723, tab. 20.figg. 



1, 2 (larva). 



delphinus, id. ibid. p. 123. 



foliaceus, Jurine, Ann. du Mus. d'Hist. Nat. tome vii. (1806) 



p. 431, pi. 26. figg. 1-21 ; Milne-Edwards, Hist. Nat. d. Crus- 



taces, iii. p. 444; Baird, British Entomostraca, p. 255, pi. 31. 



figg. 1, 2 a-l. 



Scutum cephalicum subovatum, antice utrinque parum sinuatum, 

 pedes omnes, ultimi paris exceptis, tegcns ; cauda ovata, lon- 

 gitudine circa ^ reliqui corporis, vix usque ad medium incisa, 

 laciniis apice rotundatis; stimulus longus; sipho subclavatus; 

 art. primus antennarum secundi paris aculeo valido armatus ; 

 cotyledones parvi, diametro circiter ^ corporis longitudinis 

 sequantes; pecten plaga media oblongo-rotu.ndata scabra, 

 dentibusque 3 fortibus acutis; alii dentes 2 inter maxilli- 

 pedes secundi paris adsunt. — Longit. 6-7 millim., latit. circa 

 3^ millim. (c? ?). 



Hab. in aquis dulcibus fere totius Europae, in cute externa et in cavitate 

 branchiali (?) piscium {Gasterosteorum, Cyprini carpionis, Abramis 

 hramcB*, Leucisci rutili, Tincce vulgaris, Esocis lucii, Percee fluviatilis, 

 Salmonis truita), et in larvis Ranarum parasitans. 



For a more complete synonymy we would refer to the works 



* According to Mag. Widegren. 



