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Sars in 1902 recognised the identity of Scolecithrix [Amallophora) magna (T. Scott) 

 with his Scaphocalanus acroccphalus, and revived the generic name of Amallophora for magna, 

 and two other species that were originally established in the genus. Sars left the type species, 

 Amallophora typica, in the genus Xanthocalanus. Farran (1908) points out that this revival 

 cannot be upheld as Amallophora magna is not congeneric with Amallophora typica, with which 

 I quite agree. The sensory appendages at the apex of the first pair of maxillipedes of Amallo- 

 phora magna and Amallophora typica are quite distinct, and very important differences exist 

 between the structure of the fifth pair of feet of the two sexes of both species. I agree with 

 Sars, however, that the differences between Amallophora magna, and typical Scolecithrix or 

 Scolecithricella, are worthy of generic distinction. I have already employed the name Amallophora, 

 for the separation of the type species from the genus Xanthocalanus, and another generic 

 name is necessarily required. I have, therefore, revived Sars' generic name Scaphocalanus for 

 Scolecithrix {Amallophora) magna, and the other allied species. The following are the characters 

 by which the genus can be distinguished from the other members of the family. 



The female, in general appearance, resembles the females of the genus Scolecithricella, 

 except, that it is less robust and rather more attenuated. A median crest may be present or 

 absent on the forehead. The rostrum consists of two, very long, simple filaments. The filaments 

 are slender and are gradually attenuated to a fine point at the apex. The antennules are 

 composed of twenty-three joints. The endopodite and exopodite of the antennae are of about 

 equal length. The apical portion of the first maxillipedes is similar to that of Scolecithricella. Tv/o 

 types of sensory organs are present. Some are moderately long and simple, others are short, 

 with distinctiy swollen heads. The four pairs of swimming feet are similar to those of Scoleci- 

 thricella, but the spines on the surface of the joints are stronger and more irregularly placed. 

 The terminal spine on the exopodite of the second, third and fourth pairs of feet is more 

 coarsely toothed than in Scolecithricella. The fifth pair of feet is represented by one or two free 

 joints attached to a basal part. The inner marginal spine, and the apical spine on the last 

 free joint is of considerable length. 



The male resembles the female in appearance, but there is no tracé of a crest in the 

 males of those females that possess one. The mouth organs are considerably reduced. The 

 fifth pair of feet forms a well developed prehensile organ. Each foot consists of a two-jointed 

 basiopodite, an exopodite and an endopodite. The second joint of the basiopodite of the right 

 foot is greatly swollen in its proximal part, where it bears a styliform endopodite. The distal end 

 of the joint is much attenuated, and the apex is produced on the inside, into a short blunt process. 

 The endopodite is two-jointed, short, and slightly curved. The second joint is usually lamelliform. 

 The two-jointed basiopodite of the left foot is long and cylindrical. The endopodite and exopodite 

 are three-jointed and subequal. The endopodite is usually a little longer than the exopodite. 



The long slender filamentary rami of the rostrum, the long spines on the apical joint 

 of the female fifth pair, and the structure of the male fifth pair of feet, easily separate this 

 genus from any of the other known members of the family. 



Three species were represented in the plankton collected by the 'Siboga', one of which 

 appears to be new. 



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