CRUSTACEA. 
855 
on Gyropeltis, are found to correspond with the second pair of feet 
in Caligus, The forked appendages in Caligus Prof. Kroyer con- 
tends are an aborted pair of feet; and what Milne-Edwards 
calls the ovate posterior bilobM abdomen and Thorell the hin- 
der part of the animal, Prof. Kroyer contends is the homo- 
logue of that portion of the pereion which he calls the genital 
somite ; and the rudimentary appendages beneath he considers 
to be the representatives of the pleon. 
These conditions, together with the occasional absence in 
certain genera of the external ovisac, and the general presence 
of three eyes placed in a triangular relation to each other, 
in certain free Copepods {Sapphirin'a) as well as in the larvae 
of these parasitic Crustacea, he thinks sufficient to preclude 
the separation of the Ar^ulidcn frotn the rest of the Sipho- 
nostomata. i • 
Argulidas. 
Prof. Heller (Reise Fregatte Novara) arranges this family into 
those which have — 
1. Pedes maxillares prinii paris in cot 3 dds magnos transformati, aculeus 
ante rostrum porrectus. ^ ^ , 
2. Pedes maxillares piimi paris subcheliformes, aculeus ante rostrum 
nullus, 
Argulus salmindj Kroy. (Naturhist. Tidssk, 1863, p. 89 & 102, tab. i. 
fig. 1 a~f, on a species of Salmon from Brazil ; A. chromidis, Kr. 1. c. pp. 92 & 
102, tab. i. fig. 2 a-c^ from Nicaragua ; A. funduli, Kr. 1. c. p. 94 & 103, 
tab. ii. fig. 1 a-e, on a Fundulus limhatus from New Orleans ; A. nattcreri 
(Kollr.*), Kr. 1. c. pp. 97 & 103, tab. i. fig. 3 on Hydrocijon hreindens 
(Cuv.) from Brazil j A. (Agenor) dactylopteriy Thorell, Q3fvers. af k. Vet.- 
Akad. Fork. 1864, p. 609, tab. xvi., on Dactylopterus voUtans (Linn.), 
Gyropeltis (llllr.), Kr. 1. c. p. 163. This new genus corresponds much with 
Argulus, but, besides minor details, differs in having prehensile hooks instead 
of suckers, and no spines under the rostrum. 
Gyropeltis longicauda (llllr.), Kr. 1. c. pp. 99 & 103, tab. i. fig. 4 a-e, on 
llydrocyon hrevidens from Brazil ; G. kollari (IDlr.), Kr. p. 103. 
Caligid^. 
Prof. Heller (Reise Novara, p. 160) tabulates the genera of 
this family according to the following outline : — 
I. Rostrum breve, crassum; palpi non articulati, spiniformes. . Caligidm. 
II. Rostrum longuni, angustum ; palpi articulati, foliacei * Pmidaridce. 
The first he divides into those which have — 
1. Annuli abdominis [pleon] tres capite connati, &c. 
* In the Danish description, p. 97, the name is given ns one of Kollar’s 
species; in the Latin, p. 103, it is ascribed to Heller. Hr. Thorell, Om 
tvenne Europciska Argulider (K. Vet.-Akad. 1864), refers it to the latter. 
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