I09 



Observation. This species has some resemblance to Sc. vitrejun Hoek collected by 

 the "Challenger" not far from Yeddo, in Japanese waters. The form of the whole capitulum, 

 that of the carina and the rostral latus show, however, its distinctness. 



31. ScalpelluDi sculptuiii n. sp. PL VIII, fig. 10. 



Valves fourteen, not covered by membrane, beautifully grooved. Carina with a flat roof 

 bordered by distinct ridges, short, hardly surpassing in length the carinal margin of the tergum. 

 Rostrum small triangular. (3ther valves of the lower whorl high. Infra-median latus narrow, 

 rectangular, with the um.bo at the ape.x. Carinal latus pentagonal, with the umbo above the 

 middle of the carinal margin. 



This pretty species is represented by one specimen only. 



Its c a p i t u 1 u m is elongate and nearly equally convex on the carinal and rostral sides. 

 It is not flat, the carina having a broad roof and the scuta being moreover rather convex. 

 The valves are not covered by membrane but show a very fine sculpture of parallel o-rooves 

 all over their surfaces. There are no membranous interspaces between the valves. The valves 

 of the lower whorl are strongly developed. 



The scutum is quadrilateral ; its occludent margin is strongly convex, its basal maro-in 

 nearly straight and much shorter than the tergal margin. The lateral margin is also straight 

 with a slight deviation near the upper extremity. 



The tergum is large, triangular. Its occludent and scutal margins are straight, its 

 carinal margin is feebly hollowed out in the upjjer and slightly convex in the lower part. The 

 apex is slightly produced and recurved. 



The carina is short, simply and not strongly bowed, with the umbo at the apex. The 

 roof is flat, increases greatly in width from above downwards and is bordered by distinct ridges. 

 The sides in the superior part are rather broad and at angles greater than 90° with the roof. 

 They are distinctly furrowed in this part. 



The upper latus is trapeziform and has the four margins nearly straight. The scutal 

 margin is the longest; where it meets with the tergal margin the apex is truncated. Here the 

 umbo forms a pointed, hardly distinguishable projection. 



The rostrum (fig. \oa) is very small and of a triangular shape. It is not covered 

 laterally by the rostral latera. 



The rostral latus is quadrangular with the rostral and lateral margins of nearly equal 

 length. Its upper margin is feebly hollowed out, its basal margin is short and straight. 



The infra- median latus is narrow and elongate. It has the umbo at the upper extremity 

 and as it has about the same breadth all over its length the .shape may be given as rectangular. 



The carinal latus is pentagonal, owing to its carinal margin being divided into two 

 parts of unequal length which form together an obtuse angle. The umbo is seated at this angle, 

 at the tip of the lower and longer part of the carinal margin. The upper part of this margin 

 is very slightly notched to receive the basal extremity of the ridge which borders the roof of 

 the carina. The upper and lateral margins of the carinal latus are of about the same length. 



109 



