108 CLAUSILIA. 



CIRCE. Schum. Venus castrensis, fig. 117 d. V. sulcatina, ara- 

 bica, pectinata, Auct. and other similar species. 



CIRRIPEDES. Lam. The tenth class of invertebrated animals, 

 so named from the curled and ciliated branchia which protrude 

 from the oval aperture of the shells. The class Cirripedes of 

 Lamarck constitutes the entire genus Lepas of Linnseus. They 

 are divided into two sections; first, Sessile Cirr. attached by the 

 basal portion of the shell; second, Pedunculated Cirr. supported 

 upon a Peduncle. Figs. 14 to 45. 



CIRROBRANCHIATA. Bl. The first order of Paracephalophora 

 Hermaphroclita, Bl. This order has been formed for the pur- 

 pose of giving a place in the system to the genus Dentalium. 

 The animal of which has lungs, consisting of numerous filaments, 

 having their basal origin in two radical lobes under the neck. 



CIRRUS. J. Sowerby (cirrus, a tendril.) Fam. Turbinacea, Bl. 

 and Lam. — Descr. Spiral, conical, with a hollow axis ; whorls 

 contiguous, numerous, rounded, or slightly angulated. — Obs. 

 This fossil genus resembles Trochus, from which it is known by 

 the deep funnel-shaped umbilicus. Fig. 349, C. nodosus. 



CISTULA. Humph. Cyclostoma, Lam. 



CLANCULUS. Montf. Trochus Pharaonis, Lam.— Obs. This, 

 with several other species, belong more properly to Monodonta, 

 Lam. Odontis, Sow. Fig. 361. 



CLATHODON. Conrad. Gnathodon, Gray. 



CLAUSILIA. Drap. (Clausium, a valve or folding door.) Fam. 

 Colimacea, Lam. Limacinea, Bl. — Descr. Spire elongated, 

 consisting of many volutions; aperture small, sub quadrate, hav- 

 ing several tooth-shaped folds on the columella. A small, elastic, 

 shelly plate, attached to the columella within, called the Clau- 

 sium, its office being to enclose the aperture when the animal 

 has retired within the shell. — Obs. This last character distin- 

 guishes it from the Pupse, to some of which it bears a very 

 near resemblance. Hab. Land, in the central and southern 

 parts of Europe, several British species. Fig. 295, C. Macas- 

 carensis. 



