M. T. Thorell on the Species of the Argulide. 441 
quorum 2 ultimi brevissimi; flagella pedum verticula media 
predita.—Long. circa 10, lat. 9 millim. (?¢). 
Hab. in America boreali (Connecticut, New Haven), in flumine Mill River, 
etiam ubi aqua marina stu crescente aque dulci admiscetur. In cavi- 
tate branchiali et in ipsis branchiis Catostomi sp. (C. bostoniensis, Le- 
sueur, aut communis, ejusd.) inventus. 
7. A. Nattereri, Hell. 
Syn. Argulus Nattereri, Heller, Sitzungsberichte d. Kais. Akad, d. Wis- 
sensch., Math.-~Naturwissensch. Cl., (1857) xxv. p. 103, taf. 1. 
figg. 4-12; Kroyer, Naturhist. Tidskr. 3die Rekke, (1863) ii. 
pp: 97, 103, tab. 1. fig. 3 a—d. 
Scutum cephalicum amplum, suborbiculatum, paullo latius quam 
longius, lobo frontali paullo prominenti, supra denticulis et 
setis scabrum, pedes omnes et basin caude tegens; cauda 
parum prominens, brevissima, longitudine circa 4, reliqui 
corporis, transverse elliptica, vix usque ad medium incisa; 
sipho magnus, subclavatus ; cotyledones magni, diametro fere 
+ longit. corporis equantes; 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. salinini, Kr.* 
Syn. Argulus salminet, Kroyer, Naturhist. Tidskr. 3die Rekke, (1863) ii. 
pp- 89, 103, tab. 1. fig. 2 a—e. 
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., 1-1 
reliqui corporis sequans ; cotyledones magni, diametro circa + 
totius corporis longitudinis equantes; pectinis dentes trun- 
cati, latiores quam longiores.—Long. circa 13, lat. 11 mil- 
lim. (2). 
Mas ditfert magnitudine plus duplo minore, scuto cephalico el- 
liptico, cauda paullo longiore quam latiore. 
Hab. in America meridionali (Brasilia, Minas Geraés), in branchiis Sal- 
mint sp. inventus. 
Of both this and the two following species Kroyer has given 
* Kroyer has Salmineus, Argulus salminez, which is probably a mistake. 
