UNIVALVES. 



PLATE VII. 



Genus. TRIPLEX. 

 Character. Shell spiral, three-formed, with a three-fold spire, armed with leafy 

 spines, placed alternately ; the beak long, and armed with a calcar or spur ; the 

 mouth oval, having a fringed edge. 



Species. 



No. 1. Triplex flexuosa. Shell white, and variegated with red; the spines 

 twisted in different ways, and irregular. A rare species from New Zealand, 

 in the Author's Museum. 



No. 2. Triplex denudata. Shell of a bright red, streaked transversely with 

 red lines ; the spines very small, and hardly visible ; the mouth white. A 

 native of Van Diemen's Land. From the Museum of Miss Barford. 



No. 3. Triplex cornuta. Shell pale yellow, with red veins ; the horns resem- 

 bling those of a young heifer, blunt at the extremities ; mouth white. Na- 

 tive place unknown. From the Museum of Mr. Adkins. 



No. 4. Triplex cornu-cervi. Shell brown, with a white mouth; the spines 

 resembling a stag's horn. A native of the South Seas. 



No. 5. Triplex pinnata. Shell white, slightly tinged with purple ; mouth white. 

 This shell has a strong resemblance to two fossil species of Triplex which 

 have been lately discovered, but which have not so large a furbelow. Its 

 native place is unknown ; but it is supposed not to be ver}^ rare, as two or 

 three specimens have occurred at different times. 



REMARKS. 



The genus Triplex presents the most elegant forms to the eye, of which the diversity is truly 

 surprising. It is not improbable that the horns may serve as a weapon of defence or annoy- 

 ance, or to facilitate the motion of the animal from side to side. They have been little known 

 or described until within these last twenty years, during which the discovery of the islands 

 in the southern latitudes has opened an amazing field for the investigation of the Naturalist. 

 The Triplex forms the connecting link between the genus Biplex and Hexaplex, both of 

 which it much resembles, the first in its undulated mouth, and the second in its calcar or 

 spur, inserted on the beak. It may perhaps be reckoned amongst the most interesting and 

 beautiful of our modern discoveries in Conchology. 



