444, M. T. Thorell on the Species of the Argulide. 
cordatum, postice parum sinuatum, non excisum, neque trun- 
cum nec pedes tegens; cauda circa } longitudinis reliqui cor- 
poris sequans, profunde incisa, iene sat longis, lanceolatis ; 
cotyledones parvi; art. primus maxillipedum secundi paris 
dentibus caret.—Longit. 10 millim., latit. 6 millim. (9). 
Hab. in America meridionali (Brasilia). Hospitium ignotum. 
Amongst all known species of Argulids this one has the head- 
shield least developed, and its appearance is therefore very dif- 
ferent from that of the others. THeller’s description is very 
brief, and leaves undetermined, as does also his figure, whether 
the animal has a sting (gadd), and whether its feet are provided 
with flagella or not. 
Obs. Argulus armiger, Mill. (Entomostraca, p. 124) = Mono- 
culus armager, Slabber*, is no Argulus, but the larva of a Cirri- 
pede. 
II. Gyropextts, Heller. 
1. G. longicauda, Hell. 
Syn. Gyropeltis longicauda, Heller, Sitzungsberichte d. Kais. Akad. d. 
Wissensch., Math.-Naturwissensch. Cl., (1857) xxv. p. 191, taf. 1. 
fige. 1-19; Kroyer, Naturhist. Tidskr. 3die Rekke, (1863) i. 
pp. 99, 103, tab. 1. fig. 4 a-e. 
Scutum cephalicum suborbiculare, amplum, omnes pedes tegens ; 
cauda longissima, 14—2-plo longior et duplo angustior quam 
seutum et reliquum corpus, fere usque ad basin in duas laci- 
nlas angustas, sensim lanceolato-acuminatas fissa; pectinis 
dentes 3 conici, acuti.—Longit. 28, latit. 11 millim. (3 @). 
Hab. in America meridionali (Brasilia), in branchiis Salmini brevidentis 
(Cuv.) inventus. 
2. G. doradis, Corn. 
Syn. Gyropeltis eras Cornalia, Mem. del R. Istit. Lombardo, (1860) 
vill. pp. 161, tab. 2. figg. 1-18. 
Scutum cephalicum suborbiculare, pedes ultimi paris vix tegens; 
cauda sat longior, reliqui corporis dimidiam longitudinem 
circiter zquans, fere usque ad basin in duas lacinias : angustas, 
sublanceolatas fissa; pectinis dentes 3 breves, acuti.—Longit. 
22, latit. 11 millim. (9). 
Hab. in America zequinoctiali, in corpore Doradis nigri Valenc. inventus. 
described. That described in vol. xxxiv. p. 225 is a Caligus (C. ameri- 
canus, Pickering & Dana), not an Argulus. 
# Natuurkundige Verlustigingen, behelzende microscopische Waarnee- 
mingen, &c. (1769), cited from P. L. St. Miiller’s German translation : 
Physikalische Belustigungen, &c. (1775) p. 19, tab. 6, fig. 1. 
