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Bulletin Vanderbilt Marine Mitseum, Vol. VI 



orbital buttress. The antennal spine is acute and is followed by a 

 postantennular ridge that is oblique and extends only halfway 

 back to the hepatic sulcus. The antennal sulcus is shallow and 

 tomentose. The hepatic tooth is acute and the hepatic sulcus clear- 

 ly defined in front of the tooth but dorsal of this hepatic spine the 

 cervical groove is scarcely distinguished. The sinuous subhepatic 

 groove and related ridge are continued almost to the branchio- 

 stegal tooth and the sulcus is tomentose. 



The abdomen is strongly compressed laterally and is carinate 

 in the median dorsal line on the second segment, the distal three- 

 fourths of the third segment and the entire fourth, fifth and sixth 

 segments, terminating in a distal tooth on this last segment. In 

 young adults this carina is an acute ridge but in older specimens, 

 from five to six inches long, the carina is sometimes weakly canali- 

 culate on the anterior three segments. The telson is triangulate, 

 with a deep longitudinal channel on the proximal three-fourths, 

 the apex is an acute tooth, flanked by a pair of articulated strong 

 spines, subdistal, one on either side of the base. There are no other 

 spines present on the telson. The lateral telsonic margins are 

 setose. The uropoda have both blades extending about one-third 

 of their length beyond the telson; the outer blade is somewhat 

 the larger and is narrowly oval, without a subdistal lateral spine. 



The thelycum consists of a broad tumid plate arising between 

 the fifth pair of legs and which is anteriorly bidentate, with the 

 anterior margin rounded, a sulcus or median pit anterior to this 

 portion, and immediately in advance of this, a wide oval plate, 

 situated between the bases of the fourth pair of legs, and having 



Text figure 4 — Parapenaeopsis sculptilis (Heller) , petasma of adult male, 



shown from posterior side, X 5. 



