CHAP. VI. TYPES OP THE SUB-GENUS BULIMUS. 179 



the name of Partula), where the margin of the aperture^ 

 instead of being completely reflected^ as in all the other 

 types, is only very much dilated or spread out. This 

 peculiar character brings us, of course, to the confines 

 of the sub-genus Bulimulus ; and by such shells as the 

 Bulimus melanostomus of Brazil (which will completely 

 answer to the characters given of Partula*) we return 

 again to B. hcemastomus. By arranging these species 

 in a column, as sectional divisions, they will be found 

 to represent the primary types of the spiral land shells 

 in the following manner : — 



Analogies of the Sectional Types of the Sub-genus Bu- 

 limus. 



Genera 



of the 

 Achat ince. 



Bulimus, 



ACHATINA. 



Sectional 

 Types or Species. 



Analogical 

 Characters. 



Sub-genera 

 of the 

 Bulimi. 



f Shell vontricose;^ 

 I spire short ; ) 

 Hamastomus. <; aperture in the |> Bulimus. 

 I typical species ] 

 [_ always rosy. J 



Interiuptus 

 Lara. 



Clausilia. Lubricus. 



Helicina. Lyotietianus. 



Ctclostoma. Australis. 



Shell more slen 

 der; spire e 

 vated. 



;n-l 



le- > Bulimulus. 



fSpire lengthened;"! 

 I basal volution J 

 ■{ smaller or very )■ Leptospira. 

 I little larger | 

 L than the next. J 



r Aperture distort 

 3 ed, with a dis- 

 i tincl notch at 

 t the base. 



\ 



Sub-genera 



of the 

 AchatincE. 



ACHATINA. 



COCHLICOPA. 



Macrospira 



GONIOSTOMA. LeUCOSTOMA ? 



fOuter lip thick-1 



I enedmoretlian J 



\ usual; a slight i. 



1 fold on the pil- J" auricula. 



I lar; aperture I 

 L ear-shaped. J 



ACHATINELLA. 



* " Partula. Conical, smooth, spire equal to aperture in length, con- 

 sisting of few whorls; aperture auriform ; outer lip reflected, broad ; inner 

 lip reflected, with a slight prominence on the columella." — iSoiverbt/'s Ma- 

 nual, p. 77. if the student turn to the figure of B. melanosto/nus Zool. 111. 

 1st Series, he will find this description perfectly applicable ; yet this latter 

 has been arranged as a Bulimus, and placed in a different family. 



N 2 



