1042 The American Naturalist. [December, 
mented ccelom; (2) a blood vascular system distinct from the celom 
and (3) a pair of nephridia in each somite; points which it seems to 
the present writer, imply only Annelid affinities since they fit Poly- 
cheetes as well as Oligoch:etes. 
A new Cambarus from Arkansas.— Cambarus faxonii sp. nov. 
Male, form 1, rostrum broad, elongate, deeply excavated above, mar- 
ins raised into sharp parallel ridges, each ending in prominent spines 
Aeumen very long and slender, curved upwards; post orbital ridges 
prominent, each ending in a prominent spine. 
Carapax cylindrical, slightly compressed, smooth; cervieal groove 
erate, a prominent spine on each side. Distance from cervical 
e to posterior margin of carapax 24 to 3 in distance from cervi- 
eal Abest to tip of acumen, and equal to length of acumen. Anterior 
1-2 of the areola narrow, its posterior portion triangular. Abdomen 
broad and slightly shorter than cephalothorax (including acumen). 
Outer posterior part of telson ending in a prominent spine inside of 
which is a much smaller spine, posterior margin of telson slightly 
emarginate. Anterior process of epistoma triangular. Basal segments of 
antennules with a spine on under inner border, about middle of segment. 
Antenne shorter than the body, antennal scale long and narrow (i 
ee 
SEKME god. 
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