l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93 



the second segment of the peckmcle is about four-sevenths the length 

 of the first, and in turn three-fifths the length of the terminal segment. 

 The second segment of the antennal peduncle on the right side reaches 

 about as far forward as the basal segment of the antennular peduncle ; 

 the fourth segment reaches nearly to the distal margin of the terminal 

 segment of the antennular peduncle ; the terminal segments of both 

 peduncles are nearly subequal in length and each about two-thirds the 

 length of the fourth segment of the antennal peduncle ; the antennal 

 peduncle of the left side seems to be placed lower, as the distal margins 

 of its several segments each fall short in turn of the forward distance 

 attained by the segments of the extended peduncle on the right side. 

 The lateral frontal spines are slender, sharp, incurved, and to some 

 degree movable, as they are joined to the front by a somewhat flexible 

 noncalcified extension of the carapace ; they lie just without the line of 

 the inner margin of the antennal peduncles. The lineae thalassinicae 

 diverge more widely anteriorly than posteriorly, and so at the front 

 the " oval " area which they appear laterally to limit seems much 

 wider there than posteriorly, thus giving the dorsum of the carapace 

 of this species an inverted wedge-shaped look unlike the other species 

 described in this paper. 



The large left cheliped has a very short carpus, which is a little 

 short of being twice as high as long. Measured on the upper border, 

 the palm is very slightly longer than the merus, and a very little 

 shorter than the movable finger, about twice the length of the carpus 

 and about one-fifth longer than the ischium ; the palm is about as wide 

 at its midpoint as the upper border is long. The ischium is armed 

 beneath the anterior end with three moderately long, slender spines, 

 toward the posterior end also with three more widely spaced, much 

 smaller, slender ones, and at a point midway between the two groups 

 there is a single spine of intermediate length ; all of the spines are 

 directed forward, as are those arming the lower border of the merus ; 

 on the latter are to be counted 12, which get smaller anteriorly, with 

 the exception of the second spine, close by the first one, which seems 

 smaller than it should be, perhaps abnormally so. The carpus and chela 

 are smooth and shining ; the upper and lower margins of the former 

 are thin, laminate, and turned over to form a serrate edge above and 

 below ; in the case of the carpus for the greater part of the hinder 

 margin this serrate edge is so turned over as not to be visible in the 

 outer, lateral view of the cheliped, except for the most anterior two 

 or three serrations at the infero-distal angle ; the upper and lower 

 margins of the palm are cristate and also serrate, but the serrations 

 are not so much turned at right angles to the perpendicular as in the 



