NO. 3536 DECAPOD CRUSTACEANS — CHACE 651 



Only the thi'ee largest males, with carapace lengths to the base of 

 the rostral smus of 14.9 to 18.0 mm., are conspicuously pubescent, and 

 the smallest of these has the matted covermg largely confined to the 

 chelipeds. Also, all of the males except the largest (the holotype) 

 have a distinct, though not always completely functional, sutiu-e 

 between the third and fourth abdominal somites. 



Distribution: Known only from the type locality off Rupert's Bay, 

 St. Helena. 



Subfamily Pisinae 



Pisa sanctaehelenae, new species 



Figure 14 



Material: Off Rupert's Bay; buoy; 0-2 meters; Feb. 11, 1963; 1 

 male, 2 ovigerous females [male is holotype, USNM 112459]. 



Description: Carapace, not including rostral and lateral spines, 

 one-sixth to one-third longer than broad. Regions well marked and 

 uneven. Cardiac region swollen, surrounded by broad, deep fiu-row 

 accentuated laterally by curved, longitudinal ridge near inner margin 

 of each metabranchial region. Intestinal region with median promi- 

 nence. Branchial region bearing lateral boss with obscure longitudinal 

 sulcus behind cervical groove and three smaller prominences in oblique 

 row across mesobranchial region, posteriormost forming blunt tooth 

 on posterolateral margin. Surface pubescence sparse, but groups of 

 hooked hairs (shown on left side of fig. 14a) on rostral spmes, on 

 anterior and posterior portions of each protogastric region, on bran- 

 chial prominences, and along margin of each branchial region. Ros- 

 tral spines divergent thi-oughout. Supraocular eave with long anterior 

 spine and distinct tooth at posterior angle. Tooth between supra- 

 ocular eave and postocular process large, vktually closing dorsal 

 margin of orbit. Strong spine on hepatic region behind postocular 

 process. Four distinct spines on lateral margin of branchial region, 

 first two close together, last largest, nearly as large as hepatic spine. 

 Basal antennal article with long anterior spine visible from above and 

 approaching preocular spine in length. Distinct tooth just posterior 

 to posterolateral angle of basal antennal article. Row of three acute 

 teeth, decreasing in size posteriorly, on each pterygostomian region. 

 Chelipeds of male about as long as carapace. Merus covered \vith 

 raised tubercles and four spines, one terminal, in dorsal midline. 

 Carpus with four rows of large tubercles delimiting three broad, 

 longitudinal sulci. Hand wath massive tubercle at dorsal articulation 

 with carpus and double row of irregular tubercles or sharp granules 

 forming shallow longitudinal sulcus in dorsal margin; ventral margin 

 with blunt carina on proximal three-fourths; outer surface micro- 



