200 CORBULID.E. 



again rises with a slightly convex inclination, forming, with 

 the incurved and moderately-sloping opposite dorsal edge a 

 slender and tubular rostrum, of which the somewhat acu- 

 minated extremity curves slightly upwards. The anterior 

 dorsal edge runs for a short distance in a nearly straight 

 and slightly ascending direction, forming a trifling angula- 

 tion with the front margin, wliich sweeps obliquely and 

 without much arcuation to the projecting and well-rounded 

 lowei- corner of the anterior extremity. The beaks are 

 small, and the umbones, especially that of the smaller 

 valves, are scarcely raised above the dorsal line. The car- 

 dinal process is small and depressed, with a short and 

 strong lateral tooth contiguous to it ; the ossicle is strong, 

 solid, elongated, and glossy. 



The larger of the si)ecimens from which this account 

 was drawn up measured nearly three-eighths of an inch in 

 length, and rather more than half as broad. 



The animal has a white mantle, with its margins united 

 in front, except anteriorly, where there is a passage for 

 a lanceolate white foot. Siphons united the branchial 

 longest, largest, and firmest ; the anal short and narrow, 

 but provided with a very fine white extensile membrane to 

 its orifice, which is protruded at pretty regular intervals 

 even beyond the branchial, and, unless closely observed, 

 appears of a lancet-shape, as if it were a membranous 

 blade. The main part of both siphons is cylindrical, 

 opaque, and of a yellow colour, with reddish or orange 

 markings ; the branchial tube is surrounded by several 

 simple white filamentary processes or cirrhi, which extend 

 beyond its extremity. 



As yet very few examples of this beautiful shell have 

 been found in the British seas. It was first taken in 1845 

 by Mr. M'Andrew and Professor E. Forbes in forty 



