CRUSTACEA DECAPOD A— BORR AD AILE. 81 



4. Sergestes cornutus, Kr., 1859. 



Sergestes cornutus, Kr0yer, K. Dansk. Videnskab. Selsk. Skr. (5), IV, pp. 249 and 277, pi. II, 

 fig. 2; Ortmann, Ergebn. Plankton-Exped., II, G, b, pp. 30 and 34 (1893); Hansen, 

 Proc. Zool. Soc. Lond. 1896, pp. 949 and 952. 



Nine specimens were taken at Stations 46, 50, G2, 66. 



5. Sergestes corniculum, Kr., 1859. 



Sergestes corniculum, Kr0yer, K. Dansk. Videnskab. Selsk. Skr. (.5), IV, pp. 2.52 and 278, 

 pi. Ill, fig. 4; Ortmann, Ergebn. Plankton-Exped., II, G, b, pp. 31 and 34 (1893); 

 Hansen, Proc. Zool. Soc. Lond. 1896, pp. 950 and 957. 



S. laciniatus, Kr^yer, loc. clL, pp. 272 and 284, pi. V, fig. 15. 



Two specimens were taken at Stations 46, 49. 



6. Sergestes semiarinis. Bate, 1888. 



Sergestes semiarmis, Bate, " Challenger " Macrura, p. 423, pi. LXVII, fig. 1 ; Ortmann, 

 Ergebn. Plankton-Exped., II, G, b, pp. 32 and 36 (1893). 



It seems not _ unlikely that this larval form is a stage of S. corniculum. One 

 specimen was taken with a crowd of earlier larvae, from the Aoanthosoma stage onwards, 

 perhaps of the same species.* 



Numerous specimens were taken at Stations 112, 127, 131. 



7. Sergestes edwardsi, Kr., 1859. 



Sergestes edwardsi, Kr^yer, K. Dansk. Videnskab. Selsk. Skr. (5), II, pp. 246 and 277, pi. IV, 

 fig. 9 ; Ortmann, Ergebn. Plankton-Exped., II, G, b, pp. 30 and 32 (1893) ; Hansen, 

 Proc. Zool. Soc. Lond. 1896, pp. 950 and 961. 



Two specimens were taken at Station 63. 



8. Sergestes vigilax, Stm., 1860. 



Sergestes vigilax, Stimpson, Proc. Acad. Philadelphia, 1860, p. 45; Ortmann, Ergebn. 

 Plankton-Exped., II, G, b, pp. 32 and 36 (1893); Hansen, Proc. Zool. Soc. Lond. 1896, 

 pp. 951 and 964. 



One immature specimen was taken by the Expedition. 

 Station 49. 



* The larvae collected by the Expedition are not described in the present report. All that need 

 here be said in regard to those found with S. semiarmis is that Ortmann (loc. cit.) records a similar case, 

 but that my larvae diflfer from his in several respects, notably in the presence of a procurved, median, 

 dorsal spine at the hinder end of the carapace, and in having on each side of the carapace two spines, not 

 three, as in Ortmann's species. The assemblage examined by Ortmann contained Elaphocaris of two 

 species. Possibly my Acanthosoma and his represent the same two species. It does not appear which, if 

 either, of them belongs to S. semiarmis, but it is remarkable that on two occasions the latter should have 

 been taken in company with larval swarms. 



