Genus LEPTACHATINA Gould, 1847. 



BY C. MONTAGUE COOKE, BISHOP MUSEUM, HONOLULU, H. I. 1 



Leptachatina GLD., Proc. Boston Soc. Nat. Hist, ii, 1847, p. 

 201; U. S. Exp. Exp. Moll., 1852, p. 88. PFEIFFEB, Malak. 

 Blatter, 1854, p. 143; Men. Hel. Viv., iv, p. 563. HARTMAN, 

 Proc. A. N. S. Phila., 1888, p. 51. H. and A. ADAMS, Gen. 

 of Rec. Moll., ii, p. 139. PEASE, P. Z. S. London, 1869, p. 

 650. GULICK, P. Z. S., 1873, p. 91. BALDWIN, Cat. Hawaiian 

 Shells, 1893, p. 10. SYKES, Fauna Hawaiiensis, ii, Mollusea, 

 1900, p. 356. 



Amastrinae with a rather small ovate or turrite shell, usu- 

 ally imperf orate, sometimes perforate, rarely umbilicate; 

 usually glossy, sometimes of a silky luster ; smooth, striate or 

 costate ; the embryonic whorls are usually smooth (subgenera 

 Leptachatina s. s., Labiella and Pauahia), sometimes striate 

 with minute spiral striae (subgenus Thaanumia) and some- 

 times costate with longitudinal (axial) costae (subgenus 

 Ilikala) ; the apex is always blunt and rounded ; the aperture 

 is slightly oblique ; the columellar fold is usually rather weak, 

 lamellate, the lamella sometimes reduced to a faint raised 

 line, usually oblique, rarely subtransverse. The animals are 

 oviparous. 



Type L. acuminata Gld. Distribution, Hawaiian Islands, 

 living on the ground (with the exception of L. arborea). 



The shells of Leptachatina are easily separated from those 

 of Amastra. In the latter genus the apex is more acute, never 

 rounded, and usually minutely striate. Amastra is vivi- 

 parous. 



Leptachatina was proposed by Gould in a note under the 

 description of acuminata, in the following words: "The clear 



1 The present paper is based on a study of the collections of the British 

 Museum, the Smithsonian Institution, the Academy of Natural Sciences of 

 Philadelphia, the Boston Society of Natural History, the Museum of Com- 

 parative Zoology, the New York State Museum and the Museum of Cornell 

 University. I wish to express my thanks to the gentlemen in charge of the 

 different collections, especially to Dr. H. A. Pilsbry, under whom this paper 

 was prepared. C. M. C. 



