12 Prof. J. C. Schiddte on the Structure of 
body-limbs are not hooked, but long prehensile organs, arti- 
culating with the body in such a manner that ar can reach far 
forward in order to catch objects, and then, folded together, 
keep that which has been caught closely under the mandibles ; 
the second pair of legs, which have the same shape but in a 
smaller size, are to be considered merely auxiliary organs. 
9. These three types may consequently be surveyed accord- 
ing to the subjomed scheme :— 
Instrumenta cibaria mordentia, libera, serie obliqua utrinque 
disposita. Hypostoma breve. Orificium oris amplum. 
Mandibule malis binis instructe, exteriore fixa. 
A. Mala exterior mandibularum mola instructa striata, 
mucronulata spinosave. 
a. Os manducatorium. 
Mala exterior mandibularum ramosa, digitate spi- 
nosa, prensoria. 
Maxille priores malis binis, exteriore subrecta, 
apice spinulosa. 
Onisct, Aselli, Idothee, Spheromata. 
B. Mandibule mola carentes. 
6. Os sectorium. 
Mala exterior mandibularum depressa, quadrata, 
margine interlore acutissimo, valide dentato. 
Maxille priores malis binis, exteriore incurva, 
multispinosa. 
Cirolane. 
c. Os morsorium. | 
Mala exterior mandibularum crassa, fornicata ; 
margine crasso, obtuso, edentulo. 
Maxillee priores mala unica, apice spinulosa. 
Serolides. 
10. Thus prepared, we may with greater confidence enter 
upon an examination of the structure of the oral sucking-ap- 
aratus in Cymothor. As examples we may take two often- 
Seatibed species, 4ga psora, Li., and Cymothoa estrum, auct., 
which represent the two types round which all the other Cy- 
mothoe gather themselves with regard to the construction of 
their sucking-apparatus. For the sake of comparison I also 
take into account the Anilocra Leachit, Kréyer, a new spe- 
cies from the West Indies, which approaches very near to A. 
laticauda, M.-K.. (Hist. Nat. des Crust. iii. 259. 6), besides a 
small species nearly related to Cymothoa sens. str., which was 
collected by Professor Kroyer, in Feb. 1840, on a fish caught 
