108 
THE VOYAGE OF H.M.S. CHALLENGER. 
The genera included in this section and represented in the Challenger 
the following : — 
collection are 
A. Endostome or palate without distinct longitudinal ridges defining the openings 
of the efferent branchial channels (family Cancridae, Dana). 
a. Fingers of the chelipedes acute 
Xanthinae, Dana). 
Cancer, Lamarck. 
Carpilius, Desmarest. 
Atergatis, de Haan. 
Lophactsea, A. Milne Edwards. 
Lophozozymus, A. Milne Edwards. 
Medseus, Dana. 
or subacute (subfamilies Cancrinse and 
Actsea, de Haan. 
Atergatopsis, A. Milne Edwards. 
Xantho, Leach. 
Xanthodes, Dana. 
Panopeus, Milne Edwards. 
Micropanope, Stimpson. 
b. Fingers of the chelipedes more or less distinctly excavated at the tips and 
spoon-shaped (subfamily Chlorodiinse, Dana). 
Etisus, Milne Edwards (pt.). 
Carpilodes, Dana. 
Zozymus, Leach. 
Actseodes, Dana. 
Leptodius, A. Milne Edwards. 
Phymodius, A. Milne Edwards . 1 
1 A remarkable parallelism in structure (exhibited in the following table, which also indicates a more natural 
classification) exists between the genera of these two subsections. Were the types in the Challenger collection more 
numerous, this parallelism could be exhibited in further detail. 
1. Carapace widely transverse. Antennules longitudinally or obliquely plicated. The flagella of the antennae 
excluded from the orbital hiatus by the enlargement of the basal antennal joint. 
Cancer , Lamarck. | Etisus, Milne Edwards. 
2; Carapace usually moderately transverse. Antennules obliquely or transversely plicated ; the flagella of the 
antennae not excluded from the orbits. 
a. Basal antennal joint produced within the interior hiatus of the orbit ; ambulatory legs not cristated. 
Carpilius, Desmarest. | Carpilodes, Dana. 
b. Basal antennal joint not produced within the interior orbital hiatus, but in contact with the front, or with 
the infero-lateral frontal process. 
* Ambulatory legs carinated or cristated. 
Atergatis, de Haan. I Lophozozymus, A. Milne Edwards. 
Lophactsea, A. Milne Edwards. 1 | Zozymus, Leach. 
** Ambulatory legs not carinated nor cristated. 
Medseus, Dana. 
Actsea, de Haan. 
Atergatopsis, A. Milne Edwards. 
Xantho, Leach. 
Xanthodes, Dana. 
Panopeus, Milne Edwards. 
Micropanope, Stimpson. 
Actseodes, Dana. 
Leptodius, A. Milne Edwards. 
Phymodius, A. Milne Edwards. 
