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the roof of the carina is quite flat in this specimen, there being- hardly a trace of the longitudinal 

 ridges which are distinct in the specimens of Station 45. This difference, however, is not considered 

 by me of sufficient importance to separate from one another forms which quite correspond in 

 other regards. Another difference is given by the two rostral latera which meet in this specimen 

 over the whole length of the rostral margins, a rounded space in the middle of this margin 

 only remaining uncovered by calcareous matter. A rostrum, however, could not be said to be 

 present in this specimen either. 



9. Scalpelluui inflahnii n. sp. PI. YII, fig. 5 and 5 a. 



Valves fourteen. Capitulum bulky, swollen, covered by a thick chitinous membrane. 

 Membranous interspaces between the valves. Umbo of the carina at some distance from the 

 apex, the valve angularly bent in consequence. Scutum and tergum imperfectly calcified and 

 not divided into two parts by a prominent ridge, their occludent margin strongly convex. Sides 

 of the carina broad ; upper latus pentagonal ; infra-median latus elongated with the umbo near 

 the base; carinal latus with the umbo near the base. Rostrum quite covered by membrane. 



This species is represented by three specimens. It is without doubt nearly related to 

 Sc. compressnm, mihi, collected by the "Challenger". Its bulkiness, the structure and imperfect 

 calcification of scutum and tergum distinguish it at once from the "Challenger" species. The 

 specimens were covered with mud; the outlines of the valves could only be made out after 

 cleaning the surface with a brush. 



The capitulum is relatively short, about one and a half times as long as broad, also 

 thick, swollen: its thickness is about 10 mm. in a specimen the capitulum of which measures 

 17,5 X 27 mm. The thick chitinous membrane which covers the valves and the interspaces 

 between them, leaves uncovered the umbonal part of the scutum and the tergum. This chitinous 

 membrane is very characteristically pigmented on some of the valves, the scutum especially. 

 The chitinous interspace between the valves is particularly broad between the carina and the 

 other valves. 



The outline of the scutum is quadrangular, it is strongly bowed in transverse direction. 

 The occludent margin is convex ; where it reaches the tergum a recurved apex is formed which 

 overlaps a part of the tergum. The calcified part consists of an elongated occludent and a 

 short and narrow tergal segment. 



The tergum is rather quadrangular than triangular. Its occludent margin is strongly 

 convex forming with the concave uppermost part of the carinal margin a distinctly recurved 

 apex. The scutal margin is nearly straight, the undermost part of the carinal margin wiiich 

 forms the fourth margin of the quadrangle is also straight. The calcified part of the tergum 

 is V-shaped and is composed of a broader occludent and a slightly narrower carinal segment. 



The carina has the umbo at some distance from the apex and the part above the 

 umbo forming an angle with the part underneath it. A roof, slightly hollowed out longitudinally 

 and growing rather wide towards the base of the valve, can be distinguished from the sides 

 which are narrow at the base and of considerable width in the uppermost part. 



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