72 IOWA STUDIES IN NATURAL HISTORY 
of the spine than on the outer side. The antennular scale, as 
figured by Rankin appears to be but half the length of the first 
joint of the peduncle, in our specimens it is almost as long as 
the first joint; basal antennal spine as long as the antennular 
scale not exceeding the first joint of the peduncle as in Ran- 
kin’s figure. The groove on the outer surface of the immovable 
finger of the larger hand is more marked or evident than shown 
in Rankin’s figure of the species. The second and fifth carpal 
articles of the second legs are each a little shorter than half the 
first; Rankin says a little longer than half the first, but in his 
figure, while the second article is about equal to half the first, 
the fifth is less than half. 
Zimmer considered a specimen from Barbados, which un- 
doubtedly represents this species, a variety of C. malleator 
(Dana).° Dana’s species differs, however, in a number of im- 
portant characters: the rostrum is quite flattened, broad and 
‘“under-cut’’ at the sides, in nigrospinatus it is but a dorsally 
blunt carina; the small accessory or secondary teeth on the or- 
bital hoods, between the orbital hoods and the rostrum are well 
marked in specimens of C. malleator as small as 15 mm. long, 
in nigrospinatus the corresponding portion of the medial border 
of the orbital hoods shows no more than a slight convexity if 
that; the antennular scale is shorter than the first segment of 
the peduncle, the second segment is scarcely, if twice the length 
of the third; the basal antennal spine reaches nearly to the 
middle of the second segment of the antennular peduncle; the 
antennal scale is but very little longer than the antennular 
peduncle and shorter than the antennal peduncle, in C. nigros- 
pinatus the spine of the scale is as long as the antennal peduncle 
being distinctly longer than the antennular peduncle. C. mal- 
leator is a very distinctive species by virtue of the outwardly 
directed, forward turned, process near the base of the outer 
margin of the antennal scale (already referred to, above, p. 70) ; 
this proximo-lateral angle has surely been exaggerated in Zim- 
mer’s figure (G) of his Barbados specimen, but even so, it is 
yet quite unlike the long tubercular, or spine-like basal pro- 
jection of C. malleator; in C. nigrospinatus, this outer, proximal 
5 Crust. U. 8. Expl. Exped., I (1852), p. 557, atlas (1855), pl. 31, 
figs. 9a-h. 
