PHORUS. 



Plate I. 



Genus Phorus, De Montford. 



Testa orbicularis, subconica, spird obtusd, (infractions re- 

 gularibus, peripherid iubulis cavis interdum ornatd, 

 conchyliorum lapidumque frustis, irregulariter agglu- 

 tinatis ; facie infer/id concaviusculd, granosd ant la- 

 mellosd ; vmbilico amplo, profunda, scape mtate occul- 

 lato ; aperturd depressd, marginibus disjunct is, labro 

 simplici, acuto. Operculum corneum, tenue, ovale. 



Shell orbicular, rather conical ; spire obtuse, whorls re- 

 gular, periphery sometimes ornamented with hollow 

 spines, with fragments of shells and stones irre- 

 gularly agglutinated to it ; under surface rather 

 concave, granular or lamellated ; umbilicus large 

 and deep, often concealed with age ; aperture de- 

 pressed, margins disjoined, lip simple and acute. 

 Operculum horny, thin and oval. 



The genus Phorus was introduced many years since by 

 De .Montford ; but as it was not recognized by Lamarck, 

 few authors thought it worthy of adoption. Little 

 enough is known of the nature or anatomy of the Phori, 

 but the remarkable character which their shells exhibit 

 may be sufficiently estimated to rest their claim upon that 

 alone to the rank of a genus. 



The character here alluded to is a property which 

 these mollusks possess of agglutinating to the outer sur- 

 face of their shells any fragments of stones, shells, corals, 

 or other marine debris that they may chance to be in 

 contact with, and which become so firmly attached that 

 they cannot be dislodged without violence. The well- 

 known Carrier Trbehus (Trochus agglutinans, Lamarck ; 

 Phorus onustus, mihi) was for a long time the only 

 species of Phorus known ; when others even were dis- 

 covered they were only regarded as varieties of that 

 species, and the agglutinating property which they 

 showed their animal occupants to possess, was not consi- 

 dered to be of any generic importance. The distinction 

 however which De Montford assigned to these shells 

 has become of infinite value, for we now possess several 

 species of them, and the agglutinating power operates 

 in different ways in each ; some shells, for example, are 

 found with only a few small pebbles agglutinated to the 

 earlier whorls, whilst others are characterized by their 

 having only such fragments of shells or stones as are flat 

 or tile-shaped collected round the edge or periphery of the 

 whorls ; and these several methods of agglutinating are 



each confined to particular species. Other modifications 

 of this property may yet be discovered, and I trust, as 

 the Phori are not uncommon in the West Indies, that 

 they will ere long be made the subject of anatomical 

 examination. The specific differences consist, not in 

 the nature of the materials which are agglutinated, as 

 supposed by Born and others, who had their Trochi 

 lithophorus and conchijliophorus, for stones, shells and 

 corals may often be found collected on the same indivi- 

 dual ; but in the perpetuated variations of the living 

 shell. 



I see no reason at present for altering the situation 

 which is commonly assigned to these mollusks in the 

 general system ; the structure and formation of the 

 shell, as well as the presence of an operculum, seeming 

 sufficiently to indicate that they are allied to the Trochi, 

 and not to the Calyptrcex as supposed by Gray. 



Species 1. (Mus. Stainforth.) 



Phorus calculiferus. Phor. testd orbiculari, convexo- 

 conicd, luteo-rosaced, tenui, subtilissime. granosd et 

 striata, volutis calculis et conchyliorum frustis minutis 

 superne symmetric^ ornatis ; facie inferud profuse 

 granosd et striata. 

 The pebble-collecting Phorus. Shell orbicular, con- 

 vexly conical, yellowish rose-colour, thin, very 

 finely granulated and striated, whorls symmetrically 

 ornamented round the upper part with pebbles and 

 minute fragments of shells ; under surface pro- 

 fusely granulated and striated. 

 Reeve, Pro. Zool. Soc, 1S42; Conch. Syst., vol. ii. 

 pi. 215. f. 7. 



Hob. ? 



I have seen several specimens of this very pretty 

 species ; the shell is of a bright subrosaceous fawn- 

 colour, entirely covered with fine diagonal stria? and 

 cross grains. The agglutinating property being con- 

 fined to the upper portion of the whorls, there is always 

 a row of fine pebbles or shells around the sutures, and 

 they exhibit a regular increase in their selection as the 

 agglutinating surface increases with the growth of the 

 shell. 



Species 2. (Mus. Stainforth.) 

 Phorus Indicus. Phor. testd orbiculari, convexo-conicd, 



March 1843. 



