182 SHELLS AND SHELL-FISH. PART I* 



If, therefore^ the Auricula Midce* and Judce belong 

 to the division of which Melampus is the type, they can 

 be SO arranged, without any detriment to the above table. 

 The same may be said of Scarabus. We have, indeed, 

 formed this arrangement in conformity with the struc- 

 ture of the animals, rather than of their shells ; and 

 resting upon this principle, we deem it preferable to err 

 on the safe side, rather than to follow previous authori- 

 ties on the subject. 



(169.) The next genus, Clausilia, has hitherto been 

 thought to form a part of the Pupce; the two, indeed, 

 are united, yet they appear to form distinct groups. The 

 present is distinguished by having the aperture ovate 

 and ear-shaped; while in Pupa it is almost, if not quite, 

 circular. The ClausilicB, as a whole, possess the follow- 

 ing characters : — the spire is invariably longer than the 

 aperture, which is defended in all but one instance (^Ba- 

 lia Gray) with little ridged teeth, usually placed upon 

 fto^Alips; they are all small and slender shells; and inhabit 

 temperate rather than tropical climates. We arrange 

 them as follows: — 1. Clausilia, where the thickest or 

 largest whorls are generally in the middle of the spire, 

 the tip of which usually falls off when the animal has 

 added new whorls to its shell, — a wise provision of nature, 

 observes Guilding, '^ since, its foot being short, it would 

 not have the power of drawing along so heavy a shell :" 

 the aperture is usually sinistral, but in the aberrant 

 species it is on the right side ; it is very small, much 

 contracted above, and is generally beset with teeth on 

 both its sides. In Balia, however, these teeth disappear, 

 and the mouth is dextral. The third, Macrodontes Sw., 

 is a new and most interesting type, uniting the com- 

 pressed teeth of Clausilia, with the form and size of 

 Auricula. The few species we have yet seen of these 



* The representations of the animal of Auricula Midce, given by M. 

 Lesson's Atlas (pi. 9. fig. 1.), are totally different from that of M. Quoy's: 

 the former has the tentacula and eyes of a Helix, the latter those of Sca- 

 rabus — There must be some great error in one of these ! Is M. Lesson's 

 design correct ? 



