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Genus 1. TEREBRA, Bruguiere. 



Animal ; disc short, very thick and muscular ; head proboscis- 

 shaped, cylindrical, tentacles short and conical with an eye 

 situated on the outer side of each at the base; respiratory 

 siphon cylindrical, rather prolonged. 



Shell; elongated, turriculated, sinuated at the base ; whorls very 

 numerous, but slightly convex, apex very sharp and elevated ; 

 aperture small ; columella swollen, contorted, terminating in a 

 point ; lip simple. Operculum horny, imbricated. 



The genus Terebra is one of those well-defined groups winch cannot 

 easily be confounded with any other ; it is distinguished by a long subulate 

 shell, composed of a number of small whorls tapering gradually to a point, 

 as sharp as a needle, and the base of the aperture is invariably sinuated. 

 The shell of Turritella has very much the form of Terebra, but the aperture 

 is rounded and entire ; so that Terebra may be likened to a very long 

 drawn-out Buccinum, and Turritella to a similarly elongated Turbo. The 

 shells of these genera may, however, be readily distinguished from each 

 other without referring to the generic peculiarities of the aperture. The 

 calcifying function of the animal is much the more vigorously exercised 

 in the genus under consideration, the shell is more solid, it exhibits a 

 greater variety of structural embellishment, and whilst the colours are vivid 

 and less obscure, they display a more pleasing variety of pattern and design. 



The soft parts of Terebra are naturally very limited, the head and tenta- 

 cles are small, and the entire mass when fully exserted, rarely extends 

 beyond a tenth of the shell. But although the animal is cumbered with a 

 shell ten times the length of its exserted body, it is not of the sluggish 

 character of the Mitre ; the shell of Terebra, though longer, is not of such 

 overbalancing proportions, it is more truly acuminated, the weight is chiefly 

 at the base, and the animal obtains a comparative facility of locomotion by 

 the force with which it is able to secure its muscular disc to the place 

 of attachment. 



The Terebra chiefly inhabit the eastern world, and are confined to warm 

 temperatures ; one small species, only, reaching so far north as the Medi- 

 terranean. The well-known T. maculata of Ceylon is the largest of the 

 genus, the greater number of species vary from three to four inches in 

 length, and are characterized by an interesting variety of sculpture and 

 design. The most elongated and remarkable species is the T.pretiosa, 

 which I have selected as an example on account of its rarity ; only two or 

 three specimens have yet been seen. 



