16 HELIX-AMPELITA. 



apex ; aperture ovate, whitish, a little reflexed ; upper lip depressed 

 outside. Alt. 20, diam. 47 mill. (Guilt.} 



Triton Bay, New Guinea. Very rare. 



H. undulata LE GUILLOU, Revue Zool. 1845, p. 187 (not H. 

 undulata Fer.). H. canaliculata PFR., Monographia i, p. 199. H. 

 (Pedinogyra) canaliculata Pfr., ALBERS Die Heliceen, 2d ed., p. 

 162. PFEIFFER, Noment. Hel. Viv., p. 184. TAPPARONE-CANEFRI. 

 Fauna Mai. della Nouva Guinea, in Ann. Mus. Civ. di Storia 

 Naturale di Genova xix, p. 160, 1883. 



A species known only by Le Guillou's original description. It is a 

 doubtful member of this subgenus ; the description seems to indicate 

 a shell resembling Macrocyclis laxata. 



Subgenus XVII. AMPELITA Beck, 1837. 



Ampelita BECK, Index Moll., p. 30. ALBERS, Die Heliceen (ed. 

 Martens), p. 163. PFR. Nomentel. Hel. Viv., p. 184. 



Plates 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 62 and 63 contain 

 figures of Ampelita. 



The subgenus Ampelita is one of the most numerous and char- 

 acteristic groups of Madagascar land shells. The species may be 

 divided into two sections: (1) AMPELITA, comprising shells of 

 (generally) large size, depressed form, the umbilicus open, the aper- 

 ture decidedly wider than high, periphery often angular or keeled, 

 peristome expanded or reflexed, surface frequently granulate or 

 sculptured ; and (2) POECILOSTYLUS, including imperforate, globose, 

 polished species, intensely colored, banded, the peristome very nar- 

 rowly expanded, aperture as high or higher than wide. 



The species are mostly known by but few examples ; the extent 

 of variation is therefore little understood, and the danger of multiply- 

 ing species founded on inconstant characters correspondingly great. 

 There are, nevertheless, a considerable number of undoubtedly well- 

 defined specific forms, and probably many more to be discovered, as 

 the island is still but imperfectly explored. Of the geographical 

 distribution of the several forms, not much is known ; I have given 

 exact localities in the text when known to me. 



The anatomy of Ampelita is unknown. 



I have grouped the species by certain obvious and natural char- 

 acters, around a number of characteristic types, as follows : 



