CYCLOTUS, 



135 



known from Cyclas by being less equilateral, and the anterior 

 side being the longest. C. Eivicola. PI. v. fig. 3. 



CTCLOBEANCHIATA. BL The third order of the second 

 section of Paracephalophora Monoica, Bl. containing no genera 

 of Testaceous Mollusca. 



CTCLOCANTHA. Swainson, 1840. A genus of " Trochid^," 

 consisting of Turbo stellaris and T. Calcar, and corresponding 

 with the genus Calcar, Montf. 



CTCLONASSA. Swainson. A genus of " Nassinse," Sw. con- 

 sisting of Nassa Neritoidea, and corresponding with the genus 

 Cyclops, Montf. 



CYCLOPHOEFS. Montf. 1810. A generic name proposed for 

 those species of Cyclostoma, Auct. which have an umbilicus. 

 C. Involvulus would be the type of this genus. PI. siv. fig. 

 304. 



CYCLOPS. Montf. Nassa Neritoidea, Auct. PL xix. fig. 424. 



CYCLOSTOMUS. Montf. 1810. (kvkXoq, cyclos, round ; aro^ia, 

 stoma, mouth.) Fam. Colimacea, Lam. Cricostomata, Bl. A 

 genus of land shells varying in shape from that of Pupa to that 

 of a flat orb ; the aperture is generally circular and the peri- 

 treme uninterrupted, thickened, and sometimes reflected, the 

 operculum is sheUy and spiral. Two other genera of land shells 

 are provided with opercula, and consequently might be con- 

 founded with this genus. In Helicina, the operculum is con- 

 centric and the peritreme is not continuous ; while in the small 

 genus hitherto almost unknown of Pupina, the peritreme is not 

 continuous, and there is a glassy enamel over the whole of the 

 external surface. The Monograph in Sowerby's Thesaurus 

 contains 175 species. The generic names Cyclostoma, Ltcika, 



CtCLOPHOETJS, CyCLOTTJS, MyXOSTOMA, PTEEOCYCIiOS, Pae- 



ciNEA, Myodoctoma, and Pomatias, represent the principal 

 forms. PL xiv. fig. 303, 304. PL xxv. fig. 529. 

 CYCLOTUS. Gruild. A sub-genus of Cyclostoma, consisting of 

 those species which are discoidal, as C. Planorbulum. Thesau- 

 rus Conchylium. PL xxv. fig. 83 to 86 ; and the species in our 

 plate xxv. fig. 531. 



