6o 



d. Carinal latus with the carinal margin divided into two parts, which meet at an obtuse angle 

 or are almost continuous wuth one another, the umbo being at the place where the two 

 parts meet. Upper part of the margin not, or only very indistinctly hollowed out. 



- Type: Scalpelbtni formosuiii n. sp. 



To this division belong 1 7 of the known species of Scalpeihiiii ; it is represented in the 

 collection of the "Siboga" by nine species: Sc. gracile n. sp.; Sc. proclive n. sp.; Sc. deforvie n. sp.; 

 Sc. trapezoideiim n. sp. ; Sc. hexagomiin n. sp. ; Sc. pracccps n. sp.; Sc. elcgans n. sp. ; Sc. 

 sciilptum n. sp. ; Sc. forinositin n. sp. 



e. Carinal latus with the carinal margin not divided into two parts, straight or very slightly 

 hollowed out, with the umbo at the base, where the carinal margin meets with the basal 

 margin. The base of the carina touches, or nearly touches, the upper extremity of the peduncle. 



Type : Scalpelhim virgattim n. sp. 

 To this division belong 7 of the known species of Scalpelhim ; of these four were collected 

 by H. M. S. "Siboga", viz.: 5^. virgatum n. sp. ; Sc. candidum n. sp. ; Sc. fjssiun n. sp. ; 

 Sc. incerfiiin n. sp. 



A. Sectio: Proto-Scalpellum 

 I. Scalpelhim pollicipedoides n. sp. PI. V, fig. 9 — 11. 



Valves fifteen, covered by thin and transparent membrane. .Scutum triangular, tergum 

 rhombiform, carina nearly straight with the apex projecting freely. Upper latus irregularly 

 triangular. Valves of the lower whorl consisting of a rostrum, three pairs of latera and a sub- 

 carina, all of them small, triangular, with the apices pointing outwards. The little male has a 

 capitulum with valves. 



This curious species is represented by half a dozen specimens. 



The capitulum is nearly trapeziform, the occludent and carinal margins running almost 

 parallel to each other. It is rather thick in the under half, flat in the upper half. The valves 

 are covered by thin, transparent membrane, and are separated from one another by chitinous 

 interspaces of a dark-brown colour. 



The scutum is rather large ; its apex projects beyond the occludent margin of the 

 tergum and is slightly produced. The lateral and basal margins pass over into one another 

 quite insensibly, so that the form of the scutum is triangular with a strongly arched basis. The 

 tergal margin is long, the occludent margin .hollowed out. 



The tergum is rhombiform and large. The part of the carinal margin above the apex of 

 the carina has about the same length as the occludent margin, the other part of the carinal margin 

 nearly equals the scutal margin. Near the apex the two terga slightly diverge from one another. 



The carina is only very feebly bowed longitudinally and has the umbo at the apex 

 which in the largest specimen projects freely. The carina has no flat roof but is laterally bowed 

 and not very deeply keeled. The wadth increases from the apex to the base; the surface is not 

 smooth but feebly, transversely hollowed out at five places over its length. 



The upper latus is small, of triangular shape, with the scutal margin strongly hollowed 



60 



