M. T. Thorell on the Species of the Argulidre. 441 



quorum 2 ultimi brevissimi ; flagella pedum verticula media 

 prsedita. — Long, circa 10, lat. 9 millim. ( ? ). 



Hab. in America boreali (Connecticut, New Haven), in flumine Mill River, 

 etiam ubi aqua marina ajstu cresccnte aquae dulci admiscetur. In cavi- 

 tate branchiali et in ipsis branchiis Catostomi sp. (C. hostoniensis, Le- 

 sueur, aut communis, ejusd.) inventus. 



7. A. Nattereri, Hell. 



Syn. Argulus Nattereri, Heller, Sitzungsberichte d. Kais. Akad, d.Wis- 

 sensch., Math.-Naturwissensch. CI., (1857) xxv. p. 103, taf. 1. 

 figg. 4-12; Kroyer, Naturliist. Tidskr. 3die Rskke, (1863) ii. 

 pp. 97, 103, tab. 1. fig. 3a-d. 



Scutum ceplialicum amplum, suborbiculatum, paullo latius quam 

 longius, lobo frontali paullo prominentia supra denticulis et 

 setis scabrum, pedes omnes et basin caudse tegens ; cauda 

 parum prominens, brevissima, longitudine circa --q reliqui 

 corporis, transverse elliptica, vix usque ad medium incisa; 

 sipho magnus, subclavatus ; cotyledones magni, diametro fere 

 J longit. corporis sequantes; pectinis dentes 3 longi, sub- 

 acuminati. — Longit. circa 12, lat. 13 millim. ( ? ). 



Hab. in America meridionali (Brasilia) : in branchiis et cute Salmini {Hy- 

 drocyonis) brevidentis, Cuv. {Salmini Cuvieri, Val.), inventus. 



This well-marked species is fully described and figured both 

 by Heller and Kroyer. The former has given special attention 

 to the oral organs; and his description is more complete on this 

 point than Kroyer' s, which, however, is in other respects ampler 

 and accompanied by better figures. 



8. A. salmini, Kr.* 



Syn. Argulus salminei, Kroyer, Naturliist. Tidskr. 3die Raekke, (1863) ii. 

 pp.89, 103, tab. 1. fig. 2 a-c. 



Scutum cephalicum amplum, suborbiculatum, parum latius quam 

 longius, lobo frontali lato, prominenti, pedes omnes, exceptis 

 ultimi paris, tegens ; cauda rotundata, paullo latior quam 

 longior, fere ad tertiam longitudinis partem incisa, longit. ^—^ 

 reliqui corporis aquans ; cotyledones magni, diametro circa ^ 

 totius corporis longitudinis sequantes; pectinis dentes trun- 

 cati, latiores quam longiores. — Long, circa 13, lat. 11 mil- 

 lim. ( ?). 



Mas differt magnltudine plus duplo minore, scuto cephalico el- 

 liptico, cauda paullo longiore quam latiore. 



Hab. in America meridionali (Brasilia, Minas Geraes), in branchiis Sal' 

 mini sp. inventus. 



Of both this and the two following species Kroyer has given 

 * Kroyer has Salmineus, Argulus salminei, which is probably a miatake. 



