I lO 



The umbo of the carinal latus does not project beyond the line of the carina. The right and 

 left carinal latera meet over the whole length of the lower part of the carinal margin. 



The peduncle is very short and completely covered by rather large scales, forming 

 si.K longitudinal rows. About si.\ scales are present in each row. 



Size. The total length of the specimen representing this species is 7,6 mm., the capitulum 

 alone measuring 6,2 mm. 



The specimen was taken by H. M. S. "Siboga"" at: 



Stat. 221. November 4, 1899. Lat. 6° 24' S., Long. 124° 39' E. Depth 2798 m. Bottom: .solid 

 bluish grey mud with Foraminifera. 



Observation. This species shows some resemblance to Sc. vitmnn dredged by the 

 "Challenger" near Yeddo from a depth of 1875 fathoms (about 3375 m.). The general habitus, 

 the sculpture of the surface of the valves, the structure of the carina and the large size of the 

 valves of the lower whorl are nearly equal in both species. But in Sc. vitrenm no rostrum was 

 observed; its infra-median latus is triangular and much shorter than the other valves of the 

 lower whorl; finally, the carinal latus has the umbo at one fourth of the total length of the 

 carinal margin from the inferior extremity, not above the middle of that margin as is the case 

 in Sc. sculptuvi. Under similar circumstances (bottom mud, depth t 3000 m.), from perhaps 

 similar ancestors, two forms have developed, the distinctness of which can not be doubted 

 though their resemblance is equally striking. 



32. Scalpelbtm foruiosuiit n. sp. PI. VIII, fig. 11 and \\a. 



Valves fourteen, not or but very indistinctly covered by membrane, beautifully striated. 

 Teroum with the ape.x produced and pointed. Carina simply bowed, with the umbo at the apex, 

 with a fiat roof bordered by ridges and with the sides well-developed. Upper latus trapeziform. 

 Rostrum elongate, very narrow. \''alves of the lower whorl well-developed. Infra-median latus 

 triangular. Carinal latus pentagonal, the carinal margin consisting of two parts, forming an 

 angle where they meet. 



This fine deep-sea species is represented by two specimens collected at two difterent Stations. 



The capitulum is elongate, rather flat, with the occludent margin slightly more 

 convex than the carinal margin and the apex produced and pointed. The length of the capitulum 

 is about twice its breadth. 



The scutum is large, quadrangular, with the occludent margin strongly convex and 

 the lateral margin straight. The tergal margin is a little longer than the basal margin and 

 meets the occludent margin at the slightly recurved apex which overlaps the tergum. 



The tergum is triangular; its occludent margin is straight, or even slightly hollowed 

 out (as in the specimen figured). The scutal margin is straight and so is the carinal margin 

 with a little convexity in the lower part only. About a third of the carinal margin projects 

 beyond the apex of the carina. 



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

 with a roof and well-developed sides. The roof is rather broad at the base and is bordered by 

 distinct ridges. The sides increase but slightly in width from the base upwards. 



