208 NATURAL HISTORY. 



FAMILY IX. CAXCELLAKIAD.E. 



The animals of this family are remarkable for the simple nature of the oral apparatus, both 

 tongue and teeth being wanting ; the head, moreover, does not seem to be elongated, the rostrum 

 being rudimentary ; the operculum is also wanting. The shell has the aperture more or less 

 channelled in front, and the columella is plicated. (Adams.) 



The genus Cancelkiria* includes a large number of moderate-sized shells, the surface of which is 

 cancellated or cross-barred, or reticulated by a double series of parallel lines, one running around the shell- 

 whorls from the mouth to the apex, the others transversely, corresponding to the varices, or periodic 

 mouths, of Triton and Ranella. There are several strong oblique folds on the columella. The animal has 

 no operculum. Contrary to other members of this family, the animals in this genus are vegetable 

 feeders. They are remarkable for the elegance of their shells. Seventy species are described from the West 

 Indies, China, South America, and the Eastern Archipelago, ranging from low water to forty fathoms. 



The genus Trichotropis, of Broderip, has a turbinate and thin, somewhat elevated, shell, more 

 or less umbilicated, spirally furrowed and cancellated, often furnished with epidermal fringes on the 

 ribs; apex of spine acute, aperture pyriform, outer lip simple acute, inner lip flattened, canal 

 rudimentary. More than twelve species are described, mostly from the Northern seas, from fifteen to 

 one hundred fathoms. 



FAMILY X. PYRAMIDELLID^E. 



In this family the characters are : tongue unarmed ; teeth none, or rudimentary ; tentacles broad, 

 folded ear-shaped, eyes at their inner bases ; mantle enclosed with a siphonal fold ; foot short in 

 front, produced behind; operculum horny, sub-spiral ; shell turreted, aperture entire, columella plaited. 

 The species of this group are all marine, and probably predaceous and carnivorous, as they have a 

 retractile proboscis. 



The species of the genus Pyramidella live in sandy bays and on shallow mud-banks, con- 

 cealing themselves under the surface, and indicating their presence by forming slender raised 

 tracks. Eleven species occur in the West Indies, Mauritius, and Australia. 



The genus Odostomia includes a number of very minute shells, having the habit of Rissoce, and, 

 like them, sometimes found in brackish water. They range from low water to fifty fathoms. The 

 shell is subulate or ovate, smooth ; apex sinistral, aperture ovate, columella with a single tooth-like 

 fold, lip thin, operculum horny. About thirty-five species have been described from British, Medi- 

 terranean, and Madeiran coasts. 



The genus Chemnitzia was named in honour of Chemnitz, a distinguished German conchologist, 

 of Nuremberg, 1780-95, and the author of a great work on conchology. 



The shell is slender, many-whorled, the whorls plaited ; apex sinistral ; aperture simple, ovate ; 

 peristome incomplete ; operculum horny, sub-spiral. The animal has a long retractile proboscis ; 

 eyes at inner bases of the triangular tentacles ; foot truncated in front. 



The genus Chemnitzia is world-wide in distribution. Seventy species are recorded from low 

 water to one hundred fathoms. 



Eulimella has an elongated, solid, many-whorled, smooth, polished shell ; the mouth is sub- 

 quadrate ; peristome incomplete ; columella straight, and smooth. Four species are described : from 

 Britain, Norway, and the Mediterranean. 



Monoptygma is the name of a genus of shells of great beauty and delicacy, resembling 

 greatly elongated forms of Actceon. The animal is nearly allied to Aclis in its short tentacles, with the 

 eyes at their inner bases, rudimentary tongue, and elongated narrow foot. Twelve species are 

 recorded by Adams, from India, China, and elsewhere. 



In the genus Eidima the shell is elongated, white, smooth, polished ; the spire is produced, 

 many-whorled ; the apex is acute ; aperture oval, pointed behind ; the inner lip is reflected over the 

 pillar, the outer lip is thickened internally. The Eulimre crawl with the foot greatly in advance 

 of the head, which is usually concealed beneath the margin of the shell. Many of them have 

 distorted shells, the upper whorls being often bent or inclined out of the straight line. Twenty-six 

 species are recorded, from Cuba, Norway, Britain, Mediterranean, Australia, India, and other parts, 

 in five to ninety fathoms. 



* Latin, cancellatm, cross-barred. 



