1 I 2 



The figure of the fifth pair of feet given by Lubbock shews the right and left sides in 

 a reversed condition. The endopodite of the true right side is moderately long and curved. It 

 has a distinct tooth on the middle of the outer margin. These two points distinguish this fifth 

 pair of feet from that of any of the other known males belonging to the genus Scottocalamis. 

 The strongly curved endopodite of the right fifth foot, the very short endopodite of the left 

 foot along with the dilated inner margin of the second joint of the exopodite, are at once 

 obvious on comparing the figure of the Gulf of Guinea specimen, with the illustration given 

 in this report. This species differs entirely from Scottocalamis persecans (Giesbrecht), in the 

 length of the rostral spines, in the shape of the exopodite of the left fifth foot, and also in 

 the shape of the endopodite of the right and left sides. Farran's suggestion that it is the male 

 of Scottocalamis persecans is erroneous, as it differs from that species in the particular points 

 already mentioned. 



The absence of a terminal spine on the distal ends of the last thoracic segment shews 

 that this form cannot be the male of Scottocalamis setosus, or of Scottocalamis longispinus 

 described in the present report. 



Tribe HETERARTHANDRIA. 

 9. Family Centropagidae. 



Genus Centropages Kroyer, 1848. 



This genus was established by Kroyer in 1848. The forms belonging to it are readily 

 recognised by the structure of the fifth pair of feet of the two sexes. The exopodite of the 

 female fifth pair of feet is three-jointed. The second joint of the exopodite of the right and 

 left sides is produced internally into a strong spiniform process. The shape, length and armature 

 of the projection varies in the different species, and forms one of the characters that assist 

 in distinguishing them. In the male fifth pair of feet, the left exopodite is composed of two 

 joints. The right exopodite is three-jointed. The second and third joints are greatly developed, 

 and form a powerful chela. 



Five species were represented in the plankton collected in the Malay Archipelago by 

 the 'Siboga'. 



S" 



Centropages calanimis (Dana). 



Cyclopsina calanina Dana, 1849, p. 25. 



Centropages calanimis Giesbrecht, 1S93, p. 305, pis. 17, 18 & 38. 

 Centropages calaninus Giesbrecht & Schmeil, 1898, p. 58. 

 Centropages calanimis Cleve, 1901, p. 5. 

 Centropages calaninus A. Scott, 1902, p. 404. 

 Centropages calaninus Thompson & Scott, 1903, p. 247. 

 Centropages calaninus Wolfenden, 1905 (a), p. 1014, pi. XCVIII. 



112 



