lOO 



24. Scalpellum pocuhiiii n. sp. PI. VIII, fig. 4 and ^a. 



Valves 14 not covered by membrane. Carina simply bowed with a flat roof, bordered 

 by distinct ridges. Upper latus pentagonal with the umbo at the ape.K ; ajjex produced. Rostrum 

 narrow, slightly broader at the upper extremity. Infra-median latus irregularly wine-glass shaped, 

 with the umbo near the base. Carinal latus with the umbo not far from the base. Peduncle 

 very short. 



This species is represented by one specimen only. 



The c a p i t u 1 u m is flat, broadest about the middle of the scutum, slightly narrower 

 towards the base, distinctly pointed towards the upper extremity. The carina is not strongly 

 bowed, so that the whole capitulum looks as if slightly recurved. No membrane covers the valves. 



The scutum has the ordinary shape; its occludent margin is strongly arched. It is 

 about twice as long as broad. The apex is slightly produced and overlaps the tergum. 



The tergum is rather large; the occludent margin is nearly straight, the scutal margin 

 also straight, the carinal margin .slightly convex beneath and slightly concave above the middle. 

 The ape.x of the carina presses very .slightly into the carinal margin of the tergum. Ape.x 

 hardly produced. Growth lines visible, but not very distinct. 



The carina has a distinct roof and well-developed sides. The roof grows broader from 

 the apex to the base, the sides are broadest in the upper part. The umbo is at the apex. The 

 roof is flat, bordered by distinct ridges. 



The upper latus is pentagonal, with the scutal and tergal margins by far the longest. 

 The umbo is at the ape.x which is distinctly produced. The growth ridges are visible on this 

 valve more distinctly than on any of the others. 



The rostrum (fig. ^a) is very narrow, slightly broader towards the upper e.xtremity. 

 It does not reach quite so far downwards as the basal margin of the rostral latus. 



The rostral latus is quadrilateral. Its lateral margin is convex, its scutal margin 

 slightly hollowed out. The umbo is at the angle of the rostral and scutal margins. 



The infra -median latus has the shape of a wine-glass, more or less inclined to 

 one side. Though the name I propose for the species was chosen from this characteristic, I do 

 not consider the shape of this valve of so essential importance : I afterwards discovered that 

 the right infra-median latus .shows by no means the same shape so distinctly as the left. 



The carinal latus is rather large with a long carinal margin and the umbo seated 

 near the base. The lateral margin which is sinuous in the valve of the left side, describes a 

 nearly regular curvature in the same valve of the right side of the capitulum. 



The peduncle is very .short, the .scales are relatively large and not numerous; they 

 cover the whole surface and are much pressed together. 



Size. The total length of the specimen is 6,6 mm., that of the capitulum 5,3 mm. 



The "Siboga" collected the single specimen at: 



Stat. 300. January 30, 1900. Lat. io°4S'.6S., Long. I23°23'.i E. Depth 918 m. Bottom: fine 

 grey mud. 



Observation. This curious deep-sea species may be easily distinguished from the 



