632 PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 118 



I960; 1 dried female. — James Bay, Jamestown Jetty; Feb. 1, 1962; 

 2 dried males. 



Measurements: Carapace lengths of males to midpoint of imaginary 

 line joining inner orbital angles, 77 and 94 mm.; of female, 100 mm.; 

 of postlarva, 15 mm. 



Remarks: This species, known on St. Helena as the "stump," 

 supports a local fishery (see Cunningham and Colman references). ' 



There has been no opportunity to compare these specimens with 

 West African material, but they differ from the Mediterranean Scyl- 

 larides latus in the characters noted by Holthuis (1952b). Stebbmg's 

 record of S. elisabethae from "Off St. Helena harbour, between 45 and 

 55 fathoms; June 2, 1904" is puzzling. It seems unlikely that a 

 person of Stebbing's ability and experience would confuse S. herklotsii 

 (which has subrectangular anterolateral angles and a shallow notch 

 in the lateral margin of the carapace) with the South African species 

 (which apparently has acute and outstanding anterolateral angles and 

 correspondingly pronounced indentations behmd them) . I considered 

 the chance that "St. Helena harbour" might refer to Saint Helena 

 Bay, South Africa, but the fact that the date corresponds with that of 

 collections oiAlhunea and Grapsus from James Bay, St. Helena Island, 

 seems to rule out that possibility. 



Although it has been well established that the species assigned to 

 the genus Pseudibacus are postlarvae of Scyllarides (see Bouvier, 

 1917, p. 101), these stages are not yet well known, and their identity 

 with the respective adult forms remains to be verified in most cases. 

 I have therefore illustrated the pseudibacus stage (fig. 5) found on 

 the buoy off Rupert's Bay. This specimen was evidently about to 

 metamorphose when collected. It agrees with the rather brief de- 

 scription of the Mediterranean Pseudibacus veranyi Guerin-MeneviUe, 

 1855 (which is almost certainly the postlarva of Scyllarides latus), but 

 there is little similarity between the St. Helena example and Guerin- 

 Meneville's obviously inaccurate figure. Both Pseudibacus gerst- 

 aeckeri Pfeffer, 1881, from the western South Atlantic [which Bouvier 

 tentatively assigned to Scyllarides aequinoctialis (Lund)], and P. 

 pfeferi Miers, 1882, from Mauritius [which may be the postlarva of 

 S. squamosus (H. Milne Edwards)], seem to differ from the St. Helena 

 specimen in having a distinct median carina on the carapace. In the 

 postlarva figured by Barnard (1950, p. 559, figs. 104g-k), the antero- 

 lateral angles are more outstanding, as might be expected of S. elis- 

 abethae. Probably du'ect comparison of the pseudibacus stages of S. 

 latus and S. herklotsii will be necessary to determine whether there 

 is postlarval evidence to support the belief that the two forms are 

 specifically distinct. 



