PLANISPIRA. Ill 



-of ribs will prove to be a character not without exceptions in this, as 

 in some allied genera. 



The genus is divided into four well-defined subgenera : 



* Shell white or light colored, generally banded, smooth, the 

 earlier whorls flat or concave. 



Subgenus PLANISPIRA (restricted). Shell with no crest-like ridge 

 behind the lip ; aperture decidedly wider than high, the basal lip 

 usually somewhat thickened or toothed. Penis having a flagellum. 



Subgenus CRISTIGIBBA Tap.-Can. Shell with a crest or swollen 

 ridge behind the lip; aperture about as high as wide, the basal 

 lip narrow, not thickened or toothed. Penis very short, the retrac- 

 tor and vas deferens inserted at its apex ; no flagellum. 



* Shell often roughly sculptured, the earlier whorls not 

 especially depressed. 



Subgenus ANGASELLA A. Ad. Shell depressed, the whorls tub- 

 ular, costulate or granulated ; aperture rounded or angular, the lip 

 well expanded, reflexed below. Australian species. 



Subgenus TRACHIA Alb. Shell varying from discoidal to de- 

 pressed globose, generally banded on an opaque whitish ground. 

 Last whorl deeply deflexed in front. Lip expanded, reflexed below. 

 Anatomy as in Planispira except that the jaw is ribbed. Indo-Ma- 

 layan species. 



Subgenus PLANISPIRA Beck. 

 Anatomy described above. 



( Group of P. zonaria). 



P. zebra Pfr., vi, 275. v. instricta Mart. [280. 



guttata LeGuill. edentata Mart. 



v. embrechtiana Mouss., vi, P. aurita Mart., vi, 281. 



P. iaddse Pils., vi, 276. [275. P. biconvexa Mart., vi, 281. 



P. halmaherica Strub., viii, 284. P. scheepraakeri Pfr., vi, 282. 



P. chariessa Pils., vi, 279. P. zonaria Linn., vi, 277. 



P. quadrifasciata LeGuill., vi, /. lineolata Mart. 



