142 



Genus 13. PHORUS, Be Montford. 



Animal ; ? 



Shell; orbicular, rather conical, sometimes largely umbilicated, 

 spire short, obtuse, whorls regular, more or less covered with 

 agglutinated fragments of stones, shells, Sfc, sometimes fur- 

 nished at the periphery with spouted tubes ; wider surface 

 rather concave, granular, striated or lamellated ; aperture 

 somewhat depressed, not pearly, margins disjoined, lip simple 

 and acute. Operculum thin, horny, oval. 



The Carrier Trochus shell has always been an object of interest on 

 account of the singular manner in which it is loaded with fragments of 

 stones, shells, corals, or any marine d^ris with wliich it may chance to 

 have been in contact. It would appear as though its animal occupant 

 were furnished with a powerful kind of cement, wliich it exudes during 

 the formation of the shell in such a manner that whatever immediate 

 substances it is able to remove, become firmly agglutinated to it, and 

 cannot afterwards be dislodged without violence ; the moUusk seems more- 

 over to mould its shell in a manner to receive them. 



For the purpose of distinguisliing the Lamarckian Trochus agglutinans, 

 long known to amateurs by its soubriquets of ' Mineralogist ' and ' Con- 

 chologist,' according to whether its burden was composed of stones or 

 shells, De Montford proposed the name of Phortis, and several species are 

 now known, in each of which the agglutinating property is differently 

 exercised. The shell varies materially from the Trochus type, being almost 

 colourless, not pearly, and of a more fragile texture ; one or two species 

 present a somewhat Cali/jitraa-WkQ aspect, but they belong evidently to an 

 animal of locomotive habits, and the whorls are more completely convo- 

 luted than in that genus. 



The distinction of species, independent of the usual characters of sculp- 

 ture, &c., is represented in the method of agglutinating as foUows : — In 

 the P. omisttis [T. agglutinans, Lamarck) the entire surface is covered 

 indiscriminately with stones, shells, or corals ; in the P. calculiferus the 

 agglutinating property is limited to the outer edge of the whorls, collecting 

 only very small stones, intermixed with shells, generally valves of Nucula 

 or Pectimculus. The P. cornigatus attaches flat fragments of shell, the 

 P. Indicus and Solaris small pebbles on the first one or two whorls only, 

 and in the P. exutus rarely more than the mark of some pebbles having 

 been at one time agglutinated is discernible. 



The P. onustiis is an inhabitant of . the West Indies, but all the other 

 species are from the eastern world, Japan, China, and the PliHippines. 



