966 THE AMERICAN NATURALIST. 
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Rostrum not strongly decurved, areola not narrow . C. virilis Hag. 
Rostrum long, antennal scale long and broad . C. montezumæ Sauss. 
Rostrum short, antennal scale short and narrow. <7 
Edges of rostrum swollen and raised, fingers gaping widely at baii: 
outer finger more or less bearded within at base. 7 
Edges of rostrum not swollen, fingers not widely gaping at ae outer 
finger not bearded Ž . . 80 
Spines of postorbital ridges ERE ; suborbital cae not sail deed 
. longulus Gir. 
Spines of postorbital ridges cone suborbital angle prodao: almost 
spiniform . . C. longulus longirostris Fax. 
Carapace TE, aes aie curving bowad front and rear; hands 
not impressed . i «C. bartonii Fab. 
Carapace cylindrical, sidés eariy parallel as far forward as cervical 
groove, then curving abruptly to base of rostrum. Hands strongly 
impressed . C. bartonii robustus Gir. 
Rostrum of oedi kisi wel ER SE lateral teeth strong 
C. clarkii Gir. 
Rostrum short, almost flat above, lateral teeth small 
C. troglodytes LeC. 
Distal end of meros with one small spine on superior surface 
C. girardianus Fax. 
Distal end of meros with two strong spines on superior surface 
f C. extraneus Hag. 
3 Proximal segment of telson with two spines on each side 
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C. evermanni Fax. 
Proximal TEN of telson with four or more spines on each side 
C. clypeatus Hag. 
Areola broad and long, with PRT sides ; carapace nearly smooth, 
very lightly granulate on the sides 5 
Areola narrow, with curved sides; carapace souls iinu on ‘aes 
sides atleast. ; ; i -a7 
Rostrum foveolate at R : À C ; apitats Cope and Pack. 
Rostrum not foveolate ; : i ; i ‘ <8 
Sides of carapace spiny . i me ear : C. pellucidus Tellk. 
Sides of carapace unarmed Žž . . C. pellucidus testii Hay 
Sides of carapace granulate and jetos ; no lateral or postorbital spines ; 
areola very narrow C. setosus Fax. 
Sides of carapace tubercalate ; Tatal ai siatorbital spines developed ; 
areola linear : : ‘ . C. acherontis Lönn. 
