MOLLUSCA. 
7(i 
but not digitated. The foot is proportionably small, and the eyes are 
supported by lateral pedicles of the tentaciila, thicker than the ten- 
tacula themselves The operculum is horny, long and narrow, and 
placed on a thin tail* * * § . In the 
Pterocera, Lam. 
The margin, in the adult, is divided into long and slender digita- 
tions, varying in number, according to the species. The animal is 
the same as that of the true Strombus f . 
In other Strombi, the sinus of the external margin is contiguous 
to the canal, forming the Rostellaria, Lam. There is usually a 
second canal ascending the spire, formed by the external margin 
and by a continuation of the columella. 
In some of them, the margin is still digitated. Their animal re- 
sembles that of a Murex, but has only a very small operculum :|;. 
In others, we merely observe a dentated margin. Their canal is 
long and straight §. 
In some again, that margin is entire ; they are the Hijjpocrenes. 
Montf. II 
ORDER VII. 
TUBULIBRANCHIATA. 
The Tubulibranchiata should be detached from the Pectini- 
branchiata, with which they are very closely allied, because the shell, 
Avhich resembles a more or less irregularly shaped tube, only spiral at 
the commencement, attaches itself to various bodies ; they conse- 
quently are deprived of copulating organs, and fecundate themselves. 
In the 
Vermetus, Adans., 
"W^e remark a tubular shell whose whorls, at an early age, still form 
a kind of spire, but then continue on in a tube more or less irregu- 
larly contorted, or bent like the tubes of a Serpula. This shell usually 
attaches itself by interlacing with others of the same species, or is 
partly enveloped by Lithophytes : the animal, having no power of 
* Nearly all the Strombi comprised in the second and third division of Gmelin, 
observing, that owing to the various degrees of development acquired by the exter- 
nal margin, there are several repetitions. 
-j- Stromhus lambis, Rondel., 79; — Martini, III, Ixxxvi, S55; — Str. chiragra, List., 
870; — Str. rnillcpeda, List., 868 , 869 ; — Str. scorpiiw. List., 867. 
X Strombus pes pelecani, L., List., 665, 866 . 
§ Strombus fusus, L., List., 854, 11 , 12, 916, 9. 
II Strombus amplus, Brander., Foss., Kant., VI, 76, or Rostellaria macroptera, 
Lam.; Str. jissureUa,L%va., Encycl. Method., p. 411, 3, a, 6 , which is not that of 
Martini, IV, clviii, 1498, 1499, dec. 
