214 



NATURAL HISTORY. 



PHORUS COXCHYLIOPHORUS. 



most numerous in the Javan and China Seas. Each species appears to have its own peculiar 

 method of collecting the fragments of shells and stones which cover the ground where it lives, and 

 each cements to the outside of the shell its particular kind of materials. The adventitious pieces of 

 shell are so disposed as not to curve downwards beyond the edge of the shell so as to impede the 

 progress of the animal, but are usually placed with their concave side uppermost." (Adams.) Nine 

 species have been described ; they are all tropical. Some species of these shells prefer to affix stones, 



whilst others select dead shells or corals for their grottoes. The 

 former are called " mineralogists " and the latter " conchologists " by 

 collectors. 



FAMILY XIX.-TURBINID.E. 



In this family the shell is turbinate, the last whorl rounded and 

 ventricose ; aperture sub-circular, inner lip smooth and simple ; 

 operculurn round, horny, with a solid convex shelly coat. In the 

 great pearly Tttrbo marmoreus, so often used for a sideboard or 

 mantelpiece ornament, the operculum frequently weighs several ounces. 

 A specimen in the Shell Gallery of the British Museum weighs more 

 than half a pound. The animal has a short proboscis ; the eyes are 

 at the outer base of the tentacles, which are long and slender; the 

 head and sides are bordered by fringed lobes and filaments. 



The shells of nearly all of the Turbinidse are brilliantly pearly when the epidermis and outer 

 layer of shell have been artificially removed. 



Genus Turbo* The shells of Turbo have solid convex whorls, often ornamented by furrows or 

 tubercles ; the aperture is large and rounded, the shell is pearly within. The outer side of the 

 operculum in some species resembles tufa deposited by a petrifying spring ; they are sometimes used 

 for ornaments. 



The Turbos inhabit the tropical seas ; sixty species have been described. They are mostly littoral. 



Genus PJiasiamlla, the " Pheasant-shell." The spire of this shell is elevated, the whorls are 



smooth and polished, the aperture 



oval, the columella flattened, and the 



outer lip thin. 



" When the animals of this genus 

 crawl, the foot appears to be divided 

 longitudinally into halves, which ad- 

 vance alternately ; when the right side 

 moves the left remains stationary, 

 and when this in turn is carried for- 

 ward the other half serves as a point 

 of support. MM. Audouin and Milne- 

 Edwards have observed that P. pullus 

 exhibits the same mode of progression, 

 which they compare to the amble or 

 canter of a horse. In Pkasianella 

 proper the tentacles are provided with 

 three cirrhi. In the smaller species, 



forming the Tricolia of Risso, the head-lobes appear to be Avanting. The larger species, all of 

 which have beautifully variegated shells, are principally from Australia and the islands of the 

 Pacific, and the smaller species are from the West Indies and the Mediterranean." (Adams.) 

 Thirty species are known living. 



Genus Imperator. The shell is like Trochus, with a flat or concave base ; the whorls are keeled 

 or stellated ; seen from above, it resembles the rowel of a spur, hence the name Spur-shell. The shell 

 is pearly within, the operculum is oblong and shelly. Twenty species are known, from South Africa, 

 India, &c. 



* Latin, turbo, a whipping-top. 



TURBO AHGYROSTOMUS. 



TURBO IMl'ERIALIS. 



