161 
ture and formation of the shell, as well as the presence of an oper- 
culum, seem sufficiently to indicate that they are allied to the Trochi, 
and not to the Calyptree, as supposed by Mr. Gray. 
“IT now proceed to lay seven species of this interesting genus 
before the Society, four of which are entirely new to me.” 
Genus PHorvus. 
Testa orbicularis, subconica, spira obtusa, anfractibus regularibus, 
peripheria tubulis cavis interdum ornata, conchyliorum lapidumque 
frustis irregulariter agglutinatis; facie infernaé concaviuscula, 
granos4 aut lamellosa; umbilico amplo, profundo, spe tate 
occultato ; apertura depress, marginibus disjunctis, labro sim- 
plici, acuto. Operculum corneum tenue, ovale. 
« Such are the characters which appear to me to apply generically 
to this group. The specific differences consist, not in the nature of 
the materials which are agglutinated, as supposed by Born and others, 
who had their Vrochi lithophorus and conchyliophorus, for stones, 
shells and corals may often be found collected on the same individual ; 
but in the perpetuated variations of the living shell, and the manner 
in which the surrounding debris become attached to it.” 
Puorvus sotaris. Phor. testd orbiculari, subconicd, paucis calculis 
versus apicem agglutinatis ; apice acuto ; superficie striis obliquis 
et undulatis inscriptd; anfractibus tubuloso-radiatis, tubulis tenui- 
bus cavis, apertis ; infernd facie plano-concavd, undulatim striatd ; 
aperturd semicordatd ; umbilico angusto. 
Reeve, Conch. Syst., vol. ii. pl. 214. f. 1 and 2; Conch. Icon. 
Phorus, pl. 2. f. 5 a and 8. 
Trochus solaris, Linneus, Lamarck, &c. 
Hab. Malacca. (Found in coarse sand at the depth of seven fa- 
thoms.) Cuming. 
« This very beautiful shell, in which the periphery of the whorls 
is extended throughout into hollow spouted spines, has never more 
than a few pebbles agglutinated to the first one or two whorls. 
‘The finest specimen I know of is in the collection of the Rev. Mr. 
Stainforth, and has furnished me with the drawing above referred to.” 
Puorvs onvustus. Phor. testd orbiculari, conicd, brunnescente-albd ; 
anfractibus subangulatis, rudibus, vel conchyliis vel lapidibus agglu- 
tinatis ; infernd facie subconcavd, rufd ; umbilico etate occultato. 
Reeve, Conch. Syst., vol. ii. pl. 214. f, 3, and 215. f. 8; Conch. 
Icon. Phorus, pl. 1. f. 3a and 6. 
Trochus agglutinans, Lamarck. 
Trochus conchyliophorus, 
Trochus lithophorus, 
Hab. West Indies. 
This is the original and best known species of the group; it is by 
far the most profusely covered, and is generally heavily laden with 
shells, stones, or~corals. 
\ auctorum. 
Puorvus Invicus. Phor. testd orbiculari, convexo-conicd, ad api- 
