CYCLOSTOUH)^. 226 



Genus Siphonana. The shell is flattened and tent-shaped, like Patella, rugose externally, 

 divided on the right side by a deep siphonal groove, which makes a slight projection 011 the margin. 

 The Xiphoiiarite live on rocks between the tide-marks. Thirty species are known, almost world-wide. 



Division b. OPERCULATA. Like the preceding division of Land Snails, these are all air-breathers, 

 but they differ in possessing a shelly or horny operculum. They are exceedingly like Periwinkles in 

 appearance. The pulmonary cavity is at the back of the neck, and quite open. 



FAMILY XXXII. CYCLOSTOMID^E. 



The eyes are slightly prominent on the outer side of tentacles, which are retractile ; the foot is 

 elongated, the muzzle long and truncated, mouth simple, operculum spiral. 



In the genus Cyclostoma, the shell is ovately turbinated, solid, covered with spiral ridges, and 

 minutely reticulated. Cyclostoma elegans may be collected in great abundance in the spring of the 

 year in Chalk districts. More than eighty species have been described from 

 South Europe, Africa, and Madagascar. 



Many of the land shells are very fine and c'ostly, but the names of 

 species, which are worth from 1 to ,3, when in good condition, are far 

 too many to be enumerated. Novelties realise higher prices, like tho 

 Cyclostoma de burghce, which was worth 5 when first brought from Mada- 

 gascar by Madame Ida PfeifFer poor restless soul ! A few Snail-shells 

 were all she obtained in compensation for a fever, which terminated her 

 wanderings and her life. 



T ,1 f, 1 i CYCLOPHOKU8, AN OPEUCU-. 



In the genus L y clop/torus * the characters are, animal with a short LATED LAND SNAIL. 

 obtuse muzzle, tentacles long, pointed, and slender, foot broad, shell rounded, 



spire depressed, umbilicate, aperture circular, lip continuous, operculum horny. There are nearly 

 100 species, which are found in India, the Philippines, &c. 



Genus Pupina. This curious little Pupa-like shell has a circular aperture and a thickened lip,, 

 notched before and behind ; the operculum is membranous and spiral. Eight species are found in 

 the Philippines, New Guinea, &c. 



FAMILY XXXIII.- JIELICIXID.E. 



Genus Helicina. The shell is flattened, globular; lip simple, expanded; operculum shelly or mem- 

 branous. The animal resembles Cyclophorus. One hundred and fifty species are met with in the- 

 West Indies, Philippines, Central America, Pacific Islands, &c. 



Genus Stoastoma,^ All the nineteen species of titoastoma proper are sculptured with spiral 

 Jines, and inhabit the island of Jamaica. 



FAMILY XXXIV. ACICULID^E. 



Genus Acicida. The shell is minute and slender, operculum hyaline. A. fusca inhabits low- 

 marshy situations at the roots of grass. Five species are described as occurring in Britain, Europe, 

 and Vanicoro. 



Genus Geomelania. The shell is minute, turreted ; whorls few, rapidly enlarging ; aperture- 

 simple, expanded. Twenty-one species are found in Jamaica. 



ORDER III. OPISTHOBRANCHIATA.J 



In this division the animal's gills are not contained in a special cavity, but are exposed on 

 the back and sides towards the rear of the body. When alarmed or removed from their native 

 element, they retract their gills and tentacles, and present the appearance of a lump of jelly. 



Division a. TECTIBKANCHIATA. The shell is rudimentary, and sometimes wanting ; the gills are 

 covered either by the shell or mantle. 



FAMILY XXX V. TO KN A TE I XID.E. 



Genus TornateUa. The shell is external, solid, spiral, many-whorled ; outer lip sharp; aperture 

 rounded in front, long, and narrow ; columella strongly folded ; operculum horny, elliptical. The 

 head is short and notched in front ; it has two flattened tentacular lobes, with small sessile eyes. 

 * Greek, cyclos, a circle, saulpkoreut, a bearer. t Greek, it on, pillared; stoma, mouth. 



I Greek, opisthcn, behind ; Iranckia, gills. 

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