Boone, Crustacea, Cruises of "Ara" and "Alva" 231 



median length, with the interorbital region 16 millimeters wide, 

 from tip to tip of the preorbital teeth. The preorbital margin is 

 typically Cayicer, with a narrowed, acuminate, median tooth, 

 which is slightly longer than the closely adjacent similar, sub- 

 median pair, the apex of this median tooth extending only as far 

 forward as does the margin of the second anterolateral tooth, 

 while the submedian pair of teeth extend only as far forward 

 as do the wider, blunter, preorbital teeth, from which they are 

 separated by a wide sinus. The anterolateral margin is widely 

 convex, cut into nine anterolateral teeth, of which the first, or 

 postorbital, is usually slightly narrower than the second. The 

 second, third, fourth and fifth and sixth teeth are each slightly 

 wider than the preceding, this increase of width becoming dis- 

 tinctly more noticeable on the seventh tooth, which \z quite one 

 and one-third times the width of the sixth tooth and subequal 

 to the eighth tooth, which is triangulate, crenulate distally, 

 whereas the first seven teeth are truncated and crenulate; the 

 ninth tooth is about as wide as the eighth but is unequally tri- 

 angulate, the anterior margin being scarcely half so long as the 

 posterior one. The tenth, or postlateral tooth, is about as wide 

 as the ninth, from which it is separated by a deep notch, the 

 distal border of the postlateral tooth being truncate, either 

 separated posteriorly by a shallow notch, or sometimes continu- 

 ous with the postlateral margin, which is sinuate-concave, con- 

 tinuous with the narrow posterior margin. The dorsal surface 

 of the carapace is finely granulose, convex in both directions, 

 with the gastric and urocardiac depressions well defined. The 

 "crown" delineated on the dorsad of the carapace, is defined by 

 a series of whitish (preserved specimen) dots which together 

 outline the typical profile design of a crown. These dots are 

 arranged in an arc (ten to twelve dots), across the anterior of 

 the gastric region, which forms the median apex of the crown, 

 laterally defined by the cervical groove, below which there radi- 

 ate on either side, on the branchial region, two separate, widely 

 curved lines of dots, defining respectively the outer lateral mar- 

 gin or band and adjacent inner band of the crown, which is 

 augmented, on the inner side, by a shorter, less regular arc of 

 dots, which curves inward to the short, strong, whitish line that 

 arises in the gastro-cardiac line, these latter defining the inner- 

 most bands of the crown. This pattern is, in part, one of the colour- 



