i°5 



considerably longer than the rostral and lateral margins. Where the upper and rostral margins 

 meet the umbo is seated, that part of the valve being distinctly produced. 



The infra-median latus is small, very narrow, elongated with the umbo at the apex. 



The carinal latus is trapeziform, with a short lateral and a much longer carinal 

 margin. The umbo is near the base; it hardly projects beyond the carina; the upper part of 

 the carinal margin is only very indistinctly hollowed out for the reception of the carina. 



The peduncle is thick, short and laterally flat. lts length is only a little greater than 

 its width and is less than '// d the length of the capitulum. It is covered with rather flat but 

 broad scales, the margins of which are not very distinct. 



Size. The total length of the specimen representing this species is 10,5 mm., that of 

 the capitulum 8 mm. 



The specimen was found along with Sc. proclive attached to the same small stem of a 

 Tubularian at : 



Stat. Sy. June 19, 1899. Lat. 0°32'S., Long. ii9°39'.8 E. Deptl-1655 m. Bottom: fine, grey mud. 



Observation. This species belongs to the same group of species or subdivision of 

 the genus as Sc. proclive, Sc. gracile, Sc. Novae-Zelandiae and a few more. It will be for 

 future investigators to settle whether or not we are entitled to consider them as so many 

 different species. 



29. Scalpclhtm gracile n. sp. PI. VIII, fig. 8. 



Valves thirteen, covered by a thin membrane. Scutum rather narrow, its tergal margin 

 less than half as long as the tergal margin of the upper latus. Carina with the umbo at the 

 apex, with a fiat roof bordered by not very prominent ridges and with the sides narrow. Upper 

 latus large, almost triangular owing to the carinal margin being very short. Infra-median latus 

 elongate, very narrow. Carinal latus with the carinal margin nearly straight and the umbo at 

 a short distance from the base. 



This species is represented by three specimens. 



The capitulum is flat, oval, twice as long as broad, with the occludent margin as 

 strongly (or slightly more) arched as the carinal margin. The surface of the valves is covered 

 by a thin membrane, to which small particles of mud etc. adhere. Hence the surface has a 

 yellowish colour-, the valves are delicately furrowed, but the furrowing is visible only after the 

 surface has been cleaned with a small brush or pencil. Valves of the lower whorl rather large. 



The scutum is elongate, more than twice as long as broad. The occludent margin is 

 distinctly bowed, the lateral margin hollowed out in the upper and convex in the lower part. 

 The tergal margin is short; it meets with the occludent margin at the apex, where a small 

 triangular projection is formed which slightly overlaps the tergum. 



The tergum is large, triangular. The occludent margin is convex, the scutal margin 

 nearly straight. The carinal margin is convex, with the exception of the upper part which is straight 

 and which meets with the occludent margin at a sharp angle : the apex is slightly recurved. 



The carina is simply and not strongly bowed. Its umbo is at the apex. The roof is 



SIBOOA-EXPEDITIE XXXI <?. 14 



