191 



Figure. 



For an illustration of this genus see woodcut in Mr. Chitty's paper in the 

 Proceedings of the Zoological Society for 1857, p. 166.* 



Genus 3. CYCLOSTOMA, Lamarck 



Animal ; with a proboscis-shaped muzzle, and two subulate ten- 

 tacles, with the eyes at their external bases ; foot ovate, fur- 

 nished with an operculum sometimes horny, sometimes calcareous, 

 fitting close to the aperture, in some insta?ices formed of several 

 whorls. 



Shell ; globosely turbinated, sometimes cylindrically turreled, form- 

 ing, not unfrequently, an open perspective umbilicus ; whorls 

 round, mostly spirally sculptured, with the lip expanded and re- 

 flected, rarely simple. 



Of all the genera of land shells this is the most comprehensive in respect 

 ofform and variety of structure. It contains shells globose and widely 

 umbilicated, and shells cylindrical convoluted so closely as to show scarcely 

 a trace of an umbilicus ; and there are peculiarities of character attaching 

 to the lip in many of the species which present good distinguishing cha- 

 racters for subgeneric division. The species known to this date are 720 

 in number, distributed into as many as forty natural groups ; and we only 

 regret that the limits of this elementary work will not admit of their being 

 separately characterized. All are operculated, and in some species the 

 operculum consists of several distinct whorls. 



Owing to the roundly turbinated form of the shell, and to the presence 

 of an operculum, the Cgclostomata known to Linuseus were not placed by 

 him in his genus Helix, but in Turbo ; and notwithstanding the difference 

 of habits, the animal has an evident relationship, not yet fully understood, 

 with Littorina, and some other of the pectinate-gilled mollusks. Their 

 geographical range is mainly tropical, only one small species being found 

 in Britain. 



* The gushing enthusiasm with which Mr. Chitty has complimented his " bosom friends " in 

 the foregoing harlequinade of proper names, identifying their memory not only with the titles 

 of species but of genera, renders tbe list of Stoastomata rather grotesque. However much Mr9. 

 Metcalfe may be delighted at hearing Mr. Metcalfe dilate upou the beauty of his Metcalfeia Met- 

 ca/feiana, we can fancy the astonishment of Mr. Wilkinson at being presented by Mrs. Wilkin- 

 son with two lovely Wil kinsonaa Wilkinsoniana ; and the familiarity with which Mrs. Wilkinson 

 is brought into generic association with Sir Robert Schomburgk, Dr. Gould, and Mr. Hanley in 

 the names Wilkinsoiuea Schomburgkiana, Gouldiana, and Hanleyana, is suggestive of flirtations 

 that can scarcely be tolerated with propriety in the conchological nomenclature. 



