88 Bulleiin, Vanderbilt Marine Museum, Vol. II 



wider than long, the upper surface ornamented with a few, scattering 

 low flat tubercles from some of which setae arise; cervical groove 

 faintly delineated. Interorbital space narrow, rostral horns subacute 

 and separated by a V-shaped sinus in young specimens ; more bluntly 

 rounded and less separated in older specimens. Pre- and postorbital 

 angles blunt, a linear, closed sinus about midway the upper orbital 

 margin; the eye protruding distinctly beyond the carapace. The 

 anterolateral margin is armed with five acute, outward and forward 

 directed teeth; of these, the first, third and fourth are subequal, the 

 second is much reduced and united at the base with the third tooth ; 

 the fifth tooth is weaker than the fourth, but is decidedly larger than 

 the second tooth. The fact that there is much individual variation in 

 the second tooth is strongly emphasized by the eleven specimens taken 

 by the ''Ara." Of these, the three largest, two males and a female, 

 show the dentition ascribed by Miers and Rathbun to quadridentata. 

 The males have the second tooth entirely obsolete, while the large 

 female has the second tooth reduced to a rudimentary tubercle on the 

 right side and an almost obsolete tubercle on the left side, while the 

 fourth left tooth has an accessory small, acute tooth at its base on the 

 posterior margin. Another female has both second teeth a rudimentary 

 nodule, but the carapace is longer than wide. The four males, about the 

 same size as the preceding female, has the second tooth larger, united 

 at its base, as in typical anisodon. Another female, of the same size 

 as the preceding, has the second teeth rudimentary, nodular, but the 

 remaining teeth very acute as in anisodon; two other females of about 

 the same size, has identical anisodon dentition, but the body is wider 

 in proportion to its length than in the typical form. Yet another fe- 

 male of about the same general size, except that it is distinctly longer 

 than wide, shows the second tooth on the left side almost as large as 

 the third tooth with which it is united at base, while on the right side 

 the second tooth is reduced to an almost invisible flat node. Another 

 female, large, as wide as long, has the left second tooth represented by 

 a large bluntly rounded node at the base of the third tooth, while the 

 second right tooth is acute, well developed, as in typical anisodon, and 

 united at base with the third tooth. The one small male taken at 

 Pilon, Cuba, of about the same size as the majority of the females, has 

 both second teeth acute, as in anisodon. The three males show the 

 fourth abdominal segment to have about the same length ratio; it is 

 worthy of note that while Dr. Rathbun states that this segment is 



