CcELiAXis, Adams and Angas, 1855. 



Distr. — 2 sp. Cape of Good Hope, Solomon's Is. G. exigua, 

 Ads. and Angas (c, 18). 



Shell dextral, umbilicated, turreted, obliquely costulate ; spire 

 usually decollate ; whorls numerous ; aperture with a parietal 

 plica or tubercle, a subcolumellar plication, and a columellar 

 lamella not visible from without ; peristome simple, continuous. . 



Perrieria, Tapparone-Canefri, 18*79. 



Di^tr. — P. ClausUidsformis, Tapparone. New Guinea. 



Shell sinistral, many-whorled, truncated at the apex ; aperture 

 elliptical ; peristome continuous ; columella twisted, dentateiy 

 truncate below. 



Approaches Clausilia. but differs by its truncated spire and 

 columella and want of plications. 



RiLLYA, Munier-Chalmas, 1883. 



Distr. — Eocene ; Paris. T^qoe, Pupa Rillyensis, Desh. 



Shell sinistral, fusiform, ventricose, apex not decollated, sharp ^r 

 aperture simple or dentate; subcolumellar plication joining a * 

 columellar lamella largely deyeloped in the interior, peristome 

 reflected. 



Clausilia, Draparnaud, 1805. 



Etym. — Diminutive of clausum, a closed place. 



Syn. — Cochlodina, Fer., 1819. 



Distr. — 700 species and varieties. Europe (mostly southern 

 and southeastern), Asia (mostly southern and western), Africa, 

 West Indies (1 sp. ), South America. Fossil, 20 sp. Carb. ; Nova 

 Scotia. Eocene — ; Gt. Britain, France. G. maxima, Grat., 

 miocene of Dax, is 2 inches long. 



Shell fusiform, usually sinistral; aperture elliptical or pyri- 

 form, with a posterior sinus, contracted by lamellae, and closed 

 when adult by a movable shelly plate (clausilium) in the neck ; 

 peristome continuous, reflected. 



Animal with a short, obtuse foot ; upper tentacles short, lower 

 very small ; respiratory and genital orifices on the left side ; jaw 

 with finely sillonated surface ; radula like Helix. G. bidens has 

 120 rows of 50 teeth ; G. nigyHcans, 90 rows of 40 teeth each. 



A peculiar and characteristic feature of the present genus is 

 that the animal is provided with an internal process called the 

 '■'• clausiliuvi''^ (iii, 42), which acts as a valve or spring-door in 

 closing the shell against all intruders, and has been first well 

 described by Mr. J. S. Miller, in the "Annals of Philosophy " for 

 1822 (vol. iii, p. 378), in the following words : — 



" Independently of the various contrivances which nature has 

 resorted to for the protection of the otherwise vulnerable mol- 

 lusca, it has taken peculiar care to guard the apertures of many 



