52 LINN^AN GENERA. 



sion ; ****pillar-lip dilated and thickened ; *****pillar-lip appearing 

 as if worn flat ; ******smooth, and not enumerated in the formei 

 divisions ; ******* angular, and not included in the former divisions ; 

 ##******tapering, subulate, and smooth. 



Buccinum Lapillus. — The Common White Buccinum. 

 Plate VIIL fig. 24. (Purpura Lapillus, Lamarck.) Oval, 

 pointed, spirally ridged, and faintly striated ; columella 

 broad, flattish, and impressed near the top; yellow, white, 

 chestnut, orange or brown, sometimes with spiral bands ,• 

 aperture oval, acute, lip thin, and slightly crenate. One 

 inch long. Inhabits the European seas. 



This is one of the shells from which the ancients are supposed to 

 have extracted their indehble purple dye, called the Tyrian purple. 

 The part containing the colouring matter, is a longitudinal vein, just 

 under the skin on the back, behind the head, appearing whiter than 

 the rest of the animal. If the vein is laid open with a needle, a tena- 

 cious yellow matter will flow, which being applied with a hair pencil 

 to linen, silk, or paper, wiU in a short time become of a bright yellow, 

 will soon change to pale green, then assume a bluish cast, and after- 

 wards a deep and brilliant purple. These changes are more or lesp 

 accelerated by the presence or absence of the solar rays : but even 

 without the influence of the sun, it Avill go through aU these change? 

 in two or three hours. Neither air, light, nor washing can afterwards 

 alter its hue. 



The Buccina generally inhabit the ocean, or its shores. 



Buccinum undatum. — The Waved Buccinum. Plate 

 II. fig. 10. Shell with from seven to eight ventricose volu- 

 tions, and undulated ribs ; transversely striated, and crossed 

 with fine longitudinal striae; pillar-lip reflected, and glabrous. 

 Inside white, or deep yellow in some. Four inches long. 



A common shell on most of the British shores. 

 F Body, M M the pillar or columella, Q canal or gutter. 



Genus 25.— STROMBUS. 



Animal a Limax ; shell univalve and spiral ; aperture 

 much dilated ; the lip expanding and produced into a groove 

 leaning to the left. 



Linnaeus divides the Strombi into four families: *lip projecting into 

 linear divisions or claws; **lobed ; ***dilated; ****tapering, with 

 a very long spire. 



