Boone, Crustacea, Cruise of "Alva," 1931 97 



ventral tooth is about halfway between the sixth rostral tooth 

 and the apex. In a short angle between each rostral tooth, dorsal 

 and ventral, and the rostrum, there is a short fringe of fine cilia, 

 especially between the second to fifth dorsal rostral teeth, where 

 the cilia extend the entire rostral margin. The proximal rostral 

 tooth of the dorsal margin is set about as far in advance of the 

 epigastric tooth as the latter is in advance of the origin of the 

 dorsal carina. The second rostral tooth is only two-thirds as far in 

 advance of the first one as the latter is separated from the gas- 

 tric tooth ; the second, third, fourth, fifth and sixth rostral teeth 

 are almost subequally spaced, but of slightly varying degrees 

 of acuteness. There is no postorbital tooth or ridge present. The 

 antennal tooth is small, acute, and is continued backward as an 

 oblique ridge to a point slightly in advance of the hepatic tooth. 

 Above and parallel with this postantennular ridge there is a mod- 

 erately deep postantennular sulcus, which is tomentose posterior- 

 ly beneath the hepatic spine. The hepatic spine is weak, acute, 

 and the hepatic sulcus is shallow and vanishes almost immediately 

 below the spine, while on the superior margin it is continuous 

 with the moderately shallow cervical groove, which vanishes about 

 midway its course to the median dorsal line. There is no hepatic 

 ridge or groove defining the branchial region anteriorly. There 

 are no other spines or grooves upon the carapace, which is mod- 

 erately compressed, laterally, and dorsally rounded, on the pos- 

 terior fourth. 



The abdominal segments are moderately compressed laterally 

 and are dorsally rounded on the anterior three segments, but on 

 the fourth and fifth segments are each rounded on the anterior 

 third, but are carinated in the median line on the posterior two- 

 thirds, these carinae terminating distally in obsolescence; the 

 sixth segment is one and two-thirds times as long as the fifth seg- 

 ment, and is definitely carinate in the median dorsal line through- 

 out its entire length, terminating posteriorly in a small point 

 above the telson. The telson is six-sevenths as long as the sixth 

 segment and is emphasized by a strong, median longitudinal sulcus 

 through the proximal three-fourths of the dorsal surface, the 

 distal fourth being smooth, rounded. On either side of this median 

 groove, the lateral portions of the telson slope rather obliquely 

 to the lateral margins, which are non-spinose, finely crenulate and 

 setose, converging distally to an acute apex. The uropoda are 



