The umbo of the carinal latus «.!< ><■-• n«<t project beyond the line of the carina. The right and 

 left carinal latera meel over the w h<»l«- length of the lower part of the carinal margin. 



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

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



Size. rhe total length of the specimen representing tliis species is 7,6 mm., the capitulum 

 alone measuring 6,2 mm. 



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



St.u. 221. November 4. 1 .1 at. 1 .■ ; S.. Long. 124 59 E. Depth 2798 m. Bottom: solid 

 bluish grey mud with Foraminif* ra. 



irvation. This species shows some resemblance to Sc. vitreum dredged by the 

 'Challenger" near Yeddo from a depth of 1 s 7 5 fathoms (about 3375 m.). The general habitus, 

 the sculpture of the surface oi the valves, the structure of the carina and the large si/c of the 

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

 served; 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. sculptum. Under similar circumstances (bottom mud, depth • 3000 mi, from perhaps 

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

 though their resemblance is equally striking. 



;2. Scalpdlum formosum n. sp. PI. VIII, fig. 11 and 1 w?. 



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

 rergum with the apex produced and pointed. Carina simply bowed, with die umbo at the apex, 

 with a flat ro<.f bordered by ridges and with the sides well-developed. Upper latus trapeziform. 

 Rostrum elongate, very narrow. Valves 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 fme deep-sea species is represented by two specimens collected at two different Stations. 



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

 nvex 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. 



no 



