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B. Species in which the carina is angularly bent, the part above the umbo 

 equalling or nearly equalling in size that beneath the umbo ; a rostrum is 

 always present ancl a sub-carina in several species. The little males have 



a capitulum with valves and a peduncle, or rudimentary valves. [Sectio: Eu-Scalpellum\ 



Number of species of this group at present known: i i. It is represented 

 in the collection of the "Siboga" by four species: Sc. rostratum Danvin; 

 Sc. Pcroni Gray; Sc. uncus n. sp. ; Sc. Stearnsi Pilsbry, var. 



C. Species in which the carina ma) - be divided into two parts : a much 

 larger part below the umbo and a smaller, sometimes even very small, 

 above ; a rostrum is present as a rule, a sub-carina never. The little males 



have rudimentary valves in a few cases, no valves as a rule. [Sectio : Meso-Scalpellum\ 



Number of species of this group at present known: 23. It is represented 

 in the collection of the "Siboga" by six species: Sc. chitinosum n. sp. ; 

 Sc. inflatum n. sp. ; Sc. javanicum n. sp. ; Sc. curiosum n. sp.; Sc. poly- 

 morphum n. sp. and Sc. distinctum Hoek. 



D. Species in which the carina is simply, as a rule strongly, bowed; a sub- 

 carina is always wanting, a rostrum often. The little males as a rule 



have no valves [Sectio: Arco-Scalpellu/n\ 



To this group belong all the remaining species of Scalpellum, about 80. It is represented 

 in the collection of the "Siboga" by 26 species; it may best be subdivided according to the 

 shape of the carinal latus. 



a. Carinal latus with the carinal margin convex and the umbo at the upper extremity, where 

 the convex carinal margin and the concave upper margin meet at a sharp angle. 



Type : Scalpellum velutinum Hoek. 

 To this division belong about 14 of the known species of Scalpellum; it is represented in 

 the collection of the "Siboga" by three species: Sc. moluccanum Hoek; Sc. hamulus n. sp. ; 

 Sc. diota n. sp. 



b. Carinal latus with the carinal margin divided into two parts which meet at an indistinct or 

 obtuse angle. Umbo at the upper extremity where the upper part of the carinal margin 

 forms an angle with the upper margin of the valve. 



Type: Scalpellum sessile n. sp. 

 Two new species collected by the "Siboga" must be considered as belonging to this 

 division: Sc. sessile n. sp.; Sc. cilialum n. sp. 



c. Carinal latus with the carinal margin divided into two parts which meet at a sharp angle at 

 the place where the umbo is situated. Upper part of the margin often hollowed out under part 

 convex, the angle formed by the two parts more or less projecting beyond the line of the carina. 



Type: Scalpellum hamatuvi G. O. Sars. 

 To this division belong about 36 of the known species of Scalpellum: it is represented in 

 the collection of the "Siboga" by seven species: Sc. discolor n. sp.; Sc. poculum n. sp.; Sc. 

 arcuatum n. sp.; Sc. imbricatum n. sp.; Sc. crinitum n. sp.; Sc. humile n. sp.; Sc.pellicatum n. sp. 



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