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times the breadth. The occludent and carinal margins are both strongly convex. The whole 

 capitulum is covered by a chi'tinous membrane, with the exception only of the apex of the tergum. 

 The shape of the valves is mostly very indistinct: though the largest specimen of Station 45 

 has been figured the shape of the latera is much more distinct in the smaller specimen of the 

 same Station. Hence for the description of these valves the smaller specimen has been mostly 

 made use of 



The scutum has the occludent margin convex and the tergal margin slightly hollowed 

 out. The calcified part is formed of two segments united at the apex : the one (the occludent 

 segment) is broader at the base and narrower towards the upper extremity, the other (the 

 tergal segment) extends along the tergum, is very narrow and shows the same width over its 

 whole length. 



The tergum has the calcified part V-shaped: a shorter and narrower occludent segment 

 and a slightly broader and longer carinal segment having their point of junction at the apex of 

 the valve. Along the occludent segment the chitinous covering forms a cushion-like investment, 

 the free margin of which is strongly arched. The apex of the tergum is recurved, bent towards 

 the carinal .side of the capitulum. 



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

 is quite covered by the chitinous membrane, the roof of the part underneath the umbo is covered 

 by a thin membrane only. Its width increases distinctly, but not very strongly from the umbo 

 downwards; its margins develop into distinct ridges. The sides are rather broad especially in 

 the uppermost part; its limits cannot, however, be made out distinctly. 



The upper latus is broad, trapeziform, the tergal and basal margins running about 

 parallel to each other. The scutal margin joins the tergal margin in a rounded or truncated angle 

 which extends to the extremity of the tergal segment of the scutum. The umbo is near the apex. 



The rostral latus is narrow or low. The basal margin is shorter than the scutal 

 margin, the lateral margin slightly convex. The rostral margin of the two rostral latera only 

 meet one another at the upper extremity. A triangular space remains between the two valves 

 which is covered by chitinous membrane only: this is most probably the place for the rostrum 

 if it were present as a calcified valve. 



The infra-median latus has the umbo near the base. Its general shape is that of 

 a tall wine-glass, almost without stalk, with a small and narrow foot and the upper part wide. 



The carinal latus has the umbo at the base, projecting beyond the line of the carina. 

 The carinal margin is strongly hollowed out; further, there can be distinguished a short and 

 straight upper margin, a slightly hollowed out lateral margin and a somewhat convex basal margin. 



The peduncle is cylindrical, compressed laterally. The scales on the surface are rather 

 broad l)ut not very prominent. They are numerous but they are not placed in regular longi- 

 tudinal rows. 



Size. The size of the largest specimen was 28 mm, total length and 21 mm. length of 

 the capitulum. 



One of the specimens is attached to a little piece of the shell of a Gastropod mollusc, 

 the other to a small black stick the nature of which is unknown to me. 



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