]()2 A REVISION OF THE ASTACID^. 



a punctate impressed line pai'allel with inner margin, and furnished with 

 rounded tubercles on inner margin. Movable finger tuberculate on outer 

 margin. Outer finger bearded below at base. Carpus broad, obliquely trun- 

 cate on the external side, punctate and tuberculate above, a strong median 

 internal spine, two small spines near on the base and one at the anterior 

 end near the articulation ; multispindus beneath, the two anterior spines the 

 largest. Meros smooth, two ante-apical spines obliquely placed on upper 

 margin, lower face with blunt biserial spines. Second pair of legs with long 

 setae near the end on inner side, not tufted as in C. immums. Third pair of 

 legs hooked. First pair of abdominal appendages long, deeply bifid, rami 

 recurved at tip, parallel, internal ramus subcylindrical, dilated and grooved 

 at tip, external ramus a little longer than the internal, laterally flattened, 

 ending in a slender, sharp point. 



Male, form II. Rostrum with small lateral teeth ; hand smaller, with 

 smaller tubercles ; hooks on third legs smaller ; third pair of abdominal 

 appendages stouter, cleft for only a short distance from the tip, tips blunt, 

 no articulation at the base in the one specimen examined. 



Female. Eostrum as in the second form of the male. Hand shorter 

 and broader, annulus ventralis with a very deeply excavated fossa. 



Measurements of male, form I. Length, 73 mm. Length of rostrum, 

 9 rmn. Breadth of rostrum at base, 5 mm. Length of areola, 11 mm. From 

 tip of rostrum to cervical groove, 25 mm. Length of chela, 35 mm. Breadth 

 of chela, 14 mm. Length of inner finger, 24 mm. Length of internal margin 

 of hand, 11 mm. 



Five specimens, one male, form I., one male, form II., and three females, 

 were collected by Prof. 0. P. Hay in Eastern Mississippi. Two of them are 

 labelled " Macon, Miss." 



Differs from C. inunnuis in its linear areola, flatter rostrum, differently 

 shaped chela, and male appendages, the rami of which are longer and less 

 strongly recurved. C. Palmcri differs from it in its quadrangular rostrum, 

 which has a longer acumen and more prominent lateral spines, narrower 

 and long-spined antennal scale, and longer areola ; the rami of the male 

 appendages (form II.) are a little longer and more widely separated. 

 C. Alabamensis differs by its wide areola, toothed and carinated rostrum, 

 etc. ; C. f<w//;/ r\w,s, by its laterally compressed carapace, wide areola, nar- 

 row cariuated rostrum, etc. 



