446 NEW GENUS AND SOME NEW SPECIES 



Diam. 1 inch. Length from the beaks to the base, 2 inches. 



Breadth 3-6 inches. 



Length from the top of wing to base, 3*4 inches. 



Shell triangular-ovate, inequilateral, subventricose, trans- 

 versely and finely wrinkled, shining ; substance of the shell 

 thin, showing the rays through it ; valves elevated into a broad 

 high wing posterior, and a small one, anterior to the beaks, 

 and connate in both ; beautifully undulated at the base and 

 top of the posterior wing ; undulations of the base commenc- 

 ing at the point of the beaks, pass on the outside of the tooth 

 to the margin in a slightly curved line, each successive wave 

 increasing in size and cutting the wrinkles of the epidermis 

 obliquely ; those of the top of the wing, when it is perfect, are 

 about the same in number, but less elevated, and closer toge- 

 ther ; they cut the wrinkles at about the same angle ; beaks 

 not prominent, crowned with about six elliptical concentric 

 undulations; ligament concealed in the wing; sinus formed 

 by the end of the ligament, sub-quadrate ; epidermis yellow 

 and purple brown, with green oblique rays, finely wrinkled, 

 smooth and shining ; the wrinkles of the anterior wing, as they 

 ascend the wing, are curved anteriorly and continuous over 

 both wiugs ; each valve furnished with a long, curved, lamel- 

 liform tooth, very small anteriorly to the beaks, larger and 

 longer posteriorly, pointed at both ends ; anterior cicatrices 

 distinct ; posterior cicatrices confluent ; dorsal cicatrices situa- 

 ted in the cavity of the beaks, very perceptible ; cavity of the 

 beaks wide and very shallow ; nacre thin, pearly, and irides- 

 cent, with tints of salmon, white and purple ; the undulations 

 very perceptible from the centre of the beaks along the base 

 of the tooth to the posterior dorsal margin. 



Remarks. — All the specimens which I have seen of this 

 remarkable species were brought from Canton. The first 

 was received by Mr Hyde about two years since, and then 

 excited much interest with our conchologists. Several speci- 

 mens more perfect were brought last summer in the " Cale- 

 donia ;" and from these specimens the description has been 



