PUPID. 73 
Ca@nmaxis, Adams and Angas, 1855. 
Distr.—2 sp. Cape of Good Hope,Solomon’s Is. C. exigua, 
Ads. and Angas (¢, 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, 1879. 
Disir.—P. Clausilixformis, Tapparone. New Guinea. 
Shell sinistral, many-whorled, truncated at the apex ; aperture 
elliptical; peristome continuous; columella twisted, dentately 
truncate below. 
Approaches Clausilia, but differs by its truncated spire and 
columella and want of plications. 
Rittya, Munier-Chalmas, 1883. 
Distr.—Kocene; Paris. Type, Pupa Rillyensis, Desh. - 
Shell sinistral, fusiform, ventricose, apex not decollated, sharp ; 
aperture simple or dentate; subcolumellar plication joining a 
columellar lamella largely developed in the interior, peristome 
reflected. 
CriausiLiA, Draparnaud, 1805. 
ELtym.—Diminutive of clausum, a closed place. 
Syn.—Cochlodina, Fer., 1819. 
Distr.—T00 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. EHocene—; Gt. Britain, France. C. maxima, Grat., 
miocene of Dax, is 2 inches long. 
Shell fusiform, usually sinistral; aperture elliptical or pyri- 
form, with a posterior sinus, contracted by lamellz, 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. C. bidens has 
120 rows of 50 teeth; C. nigricans, 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 
“clausilium” (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. ili, p. 378), in the following words :— 
“Independently of the various contrivances which nature has 
resorted to for the protection of the otherwise vulnerable mol- 
lusea, it has taken peculiar care to guard the apertures of many 
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