Upper l.iiu^ triangular with the umbo at the apex, this pari acuminated fitting into 

 the angle between the scutum and the tergum. Lateral margin com irino-lateral margin 



sirm ivex and divided into two unequal parts bj the recurved apex ol the carinal latus. 



Rostrum (fig. i£ imall, elongate, not triangular, laterally covered by the rostral latera. 



Rostral latus quadrangular, low, with the lateral margin only slightly longer than 

 the rostral margin. 



Infra-median latus small, narrow, slightly increasing from the recurved apex to 

 the base ' mbo at the ai 



i arinal latus with the umbo at the strongl) recurved apex. The carinal margin is 

 convex, the upper lateral margin hollowed «uit. 



Peduncle short, flat cylindrical, only ' "' of the length "f the capitulum. S al< rather 

 ed in five longitudinal rows. 



Size. The total length of the specimen is i<> mm., that of the capitulum about 7,5 mm. 



The specimen representing this species in the collection of the "Siboga" was taken at: 



Stat. 251. December 8, 1899. Lat. 5 28'.4 S., Long. i32°o'.2K. Depth 204 m. Bottom: hard 

 il sand. 



Observati ons. This species is nearly related to Sc. hamiilns as also to Sc. rubrum 

 Hoek which was taken by the " Challenger" near Lu/on, at a depth of 180 to 207 m. There 

 are however small differences in the shape ol the valves, ol the rostrum especially, as also in 

 the size and number of the scales of the peduncle. The description of Sc. rubrum was also 

 given from a single specimen; its capitulum measured only 5 mm. 



17. Scalpellum sessile n. sp. PI. VII, fig. [6. 



Valves thirteen, not covered by membrane. Carina short, simply bowed with the umbo 

 at the apex, no flat roof, but laterally bowed. Upper latus trapeziform. Valves of the lower 

 whorl large. Infra-median latus triangular, with the umbo at the apex and a rather broad basis. 

 Carinal latus very large, pentagonal, with the umbo at the upper extremity. 



This species is represented by four specimens, one being very small. 



The capitulum is rather thick, with the carinal margin much more bowed than the 

 occludent margin. No membra /ers the valves. Whereas the valves of tin- lower whorl are 



the scutum, tergum and carina are relatively small, the upper latus medium-sized. The 

 valves nearly touch each other; they cannot be said to be separated by chitinous interspaces. 

 The length of the capitulum is twice the breadth it has in the middle, a little above the base 

 of the carina. 



The scutum is about twice as long as broad. The occludent margin is hollowed oul 

 in the lower and convex in the upper part: the apex is produced, the tergal margin much longer 

 than the basal margin. The lateral margin is more than half the length of the occludent margin. 



The tergum is triangular; its three margins, the carinal being the longest, are convex. 



The carina is short, simply and rather strongly bowed, with the umbo at the apex. 

 • and sides are not separated by ridges, the dorsal surface of the valve being laterall) bowed. 



88 



