7'J MOLLUSCA. 



but not digitated. The foot is proportionally small, and the eyes are 

 supported by lateral pedicles of the tentacula, 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 cligita- 

 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 Hippocrenes. 

 Montf. II 



ORDER VII. 

 TUBULIBRANCHIATA. 



The Tubulibranchiata should be detached from the Pectini- 

 branchiata, with which they are very closely allied, because the shell, 

 which 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., 



We 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. 



f Strombus lambis, Rondel., 79; Martini, III, Ixxxvi, 855; Sir. chiragra, List., 

 870; Sir. millepeda, List., 868, 869; Str. scorpius, List., 867. 



J Strornbiis pes pelecani, L., List., 865, 866. 



Strombus fusus, L., List., 854, 11, 12, 916, 9. 



|| Strombus amplus, Brandcr., Foss., Hant., VI, 76, or Rostellaria macroptera, 

 Lam.; Str.fissurclla, Lam., Encycl. Method., p. 411, 3, a, 6, which is not that of 

 Martini, IV, clviii, H98, 1499, &c. 



