116 Bulletin, Vanderhilt Marine Museum, Vol. Ill 



Technical description : Carapace robust, 24 mm. long, including 

 rostrum; abdomen, 53 mm. long to tip of telson. Rostrum small, 

 scarcely reaching to the base of cornea, armed with four teeth, armed 

 distally with a short, acute tooth above and just a trifle posterior to 

 which is another smooth tooth, behind which, at a slightly greater dis- 

 tance, is the third tooth, while the fourth rostral tooth is about at the 

 beginning of the carapace. There is a laminate, median dorsal ridge 

 extending the entire length of the carapace, and produced into a 

 strong, slender, forward-directed triangulate spine about midway 

 the carapace, and behind this, about two-thirds the distance from the 

 posterior margin, is a stronger, basally broader, triangulate tooth, 

 just anterior to which the carapace is higher and convex, and behind 

 which it tapers down. There is an acute antennal spine behind which 

 the carapace is raised in a slightly carinate ridge; also a sharp 

 hepatic spine is present. The entire surface of the carapace is finely 

 ciliated, and the posterolateral margin bears a flat carina. 



The abdomen is robust with a distinctive median dorsal carina, 

 which, on the first abdominal segment, is produced anteriorly into 

 a high, prominent, laminate, triangular tooth, with the apex directed 

 forward; the epimeral region is broadly rounded, with single, short, 

 acute, forward-directed tooth. Two incomplete, transverse grooves 

 ornament the lateral region of this segment. The second segment is 

 much longer in the median line than the first, with the epimeral 

 region, which is irregularly convex marginally, with a small tooth 

 similar to that of the first segment. There are three transverse 

 grooves on the second segment, the anterior of which is near the 

 median region and terminates on either side by disappearing under 

 the overlapping first segment; the other two grooves are similarly 

 placed to those on the first segment, but are longer. The third seg- 

 ment is about as long in the median line as the second, with only two 

 transverse grooves, the epimeral margin more convex and the marginal 

 tooth more sharply outbent. The fourth abdominal segment is as long 

 in the median line as the third, and has two transverse grooves later- 

 ally. The dorsal carina is slightly excavate posteriorly ; the posterior 

 margin is incised slightly below the median lateral region, and below 

 this incision the margin is produced, convex; there is a single sharp 

 out-bent spine at the extremity of the epimeral margin. The fifth 

 abdominal segment is three-fourths as long in the median line as the 

 preceding segment and bears on the carina a subdistal tooth separated 

 by a brief concavity from the distal tooth of the carina which lies 



