S EXOTIC CONCHOLOGY. 



The chief character of the genus Pterocera, which rests on the basal lobe of 

 the outer lip being turned inwards and generally toothed, having been hitherto 

 overlooked, has caused this shell to be included in the overburdened one of Strom- 

 bus. We easily recognize the species by the peculiarity of its outer lip, which is 

 very much dilated, sinuated near the base, curved inwards in the middle, and 

 scolloped and laciniated towards its upper angle. For the rest, the shape is ovate- 

 oblong, transversely ribbed and nodolous, the colours white and yellowish orange, 

 the spire exserted and acute, the throat rosy and the mouth smooth. Length four 

 inches and a half. According to Chemnitz it is found in the East Indies. 



Genus -STROMBUS. 



Outer lip entire ; the margin not inflected, with a deep sinus near the base, and the upper 

 part not ascending to the top of the spire : basal lobe rarely inflexed and never 

 toothed. 



S. TRICORNIS. THE HORNED WING-SHELL. 



Plate XXXI. 



Testa turbinato-trigona, ponderosa, vel pallida vel albo et rufo longitudinaliter picta, nodis 

 tribus longitudinaliter compressis armato : labio exteriore inflexo, margine crasso, 

 supra attenuate et ultra acutam subnodosamque spiram producto ; cauda truncata : 

 apertura laevi, alba. 



Variety of S. Gallus, Dilw. p. 662. no. 14. 



S. Tricornis, Lam. Anx. sans V. 7. p. 201. no. 4. 



Far. A. Enc. Met. 408. fig. 1. & 409. fig. 2. Mart. 3. tab. 84. fig. 843. Lister, 873. 

 Sw. II. 1st series, part 3, pi. 135. Wood's Cat. Sup. Stromb. no. 16. 



Far. B. Mart. 3. tab. 84. fig. 844, 5. Young Shells. Seba, 62. fig. 36, 10. Mart. 

 3. fig. 847, 890. 



Martini was the first conchological writer who separated this species from 

 S. Gallus of Liimseus, under which name were included three shells so different 

 frotn each other, that they hardly possess one character in common. The one we 

 are describing is ponderous, triangularly turbinate, and armed with three longitudi- 

 nally compressed protuberances. Its outer lip is inflexed (the margin thickened) 

 attenuated above, and produced beyond its spire, which is acute and subnodulous : 

 chamiel truncated. Two varieties of this shell are met with ; the one we have 

 figured having the attenuated process of the lip much produced, the margin folded 

 inwards and the lip somewhat spatulate or spoon-shaped, the colour generally 

 white, slightly diversified with brown stripes or irregular spots, and the mouth pure 

 white : the other (var. B.) with the process of the lip shorter and the margin not 



