No. 396.] MORTH-AMERICAN INVERTEBRATES. 963 
Areola narrower. : i ‘ ; j C. meeki Fax. 
Postorbital spines wenttig : A : : i i ; es 
Postorbital spines present i 90 
Sides of rostrum converging siniforiaty to ees apex, no acumen 
C. montezume occidentalis Fax. 
Sides of rostrum angulated or = toothed near the apex, thus defin- 
ing an acumen . . C. montezume@ Sauss. 
Rostrum long and shite with stout, shat lateral spines and slender 
acumen ; postorbital spines strong. C. chapalanus Fax. 
Rostrum of medium length, with small TEER teeth and short, broad 
acumen ; postorbital spines small 7 ; i ra 
Sides of rostrum raised as sharp ridges . Ga montezume dugesii Fax. 
Sides of rostrum not raised as sharp ridges 
Branchiostegal spine not developed C. montezume brio bitis Fax. 
Branchiostegal spine developed but small ‘ . C. cubensis Erich. 
Posterior portion of carapace ara coe less than half as ae as 
anterior portion . . . 40 
Posterior portion of carapace hale: or early ‘half as long as anterior 
portion. : : ; ; : : : ‘ . 42 
Areola wide . i : i : i ; . 4! 
Areola rather narrow : c. lecoutes Hee: 
Proximal segment of ‘eion with three spines on each side 
C. angustatus LeC. 
Proximal segment of telson with four spines on each side 
C. pubescens Fax. 
Anterior border of carapace with a projecting — below the eye . 43 
Anterior border of carapace not angulate : : : 
Suborbital angle spinulose . : : 5 : i . 82 
Suborbital angle not spinulose 7 ‘ ; : ; . 44 
Rostrum nearly plane above . i è : ‘ : ; CAS 
Rostrum well excavated . : : ; ‘ i : . 46 
Acumen long . : : . . C. fordant Fax. 
_ Acumen rather short sie small : ; ‘ Sg mines Fax. 
Areola narrow ; j ; ; 4r 
Areola of ENAR or excessive width 4 ; . 48 
Margins of rostrum concave . ‘ : c meiki F ax. 
Margins of rostrum slightly convex . C. immunis spintrostris Fax. 
Areola wide . ‘ ‘ ; i 3 C. sloanii Bun. 
Areola of moderate width : i ‘ ‘ ‘ à : . 49 
Acumen of rostrum short ; ; on : : i . 50 
Acumen of rostrum not short l 5i 
Lateral teeth of rostrum wel direii but short, sides of online 
nearly parallel . C. blandingii Har. 
Lateral teeth of rosin poty devdaped, sides of rostrum convergent 
C. blandingii acutus Gir. 
