166 ACT^EON-LEUCOTINA. 



Section RICTAXIS Ball, 1871. 



Ridaxis DALL, Amer. Journ. Conch, vii, p. 136, type Tornatella 

 punctoccelata Cpr. Actceonidea GABB., Proc. Acad. Nat. Sci. Phila- i 

 delphia, 1872, p. 273, type A. oryza Gabb. 



Shell like Actceon, but with the columella obliquely truncated at 

 base or having a small projection there. 



A. PUNCTOC^ELATUS Carpenter. PI. 49, figs. 24. 



Shell oblong with conoidal spire ; white with two broad ashy or 

 or brown zones. Whorls 5, convex, separated by impressed and 

 narrowly channelled sutures. Surface sculptured throughout with 

 spiral equidistant conspicuously punctate grooves, the raised inter- 

 vals smooth except for a fine engraved line along the middle of each. 

 Grooves on body-whorl about 26. Aperture two-fifths to two-thirds 

 the length of the shell. Columella having a spiral fold above, 

 obliquely truncated at base. 



Alt. 13-5, diam. 7 mill. 



Alt. 10, diam. 4'5 mill. 



Catalina Island and San Diego, California (Cooper, Gabb. et at.*) ; 

 Monterey (Dall). 



Tornatella punctoccelata CPR., Suppl. Rep. Brit. Asso. 1863, p. 646 ; 

 Journ. de Conchyl. 1865, p. 139. Actceon (Rietaxis) punctoccelata 

 DALL, Amer. Journ. Conch, vii, p. 136. 



This species is well distinguished by the obliquely truncated base 

 of its columella. It occurs in the Pliocene of San Diego Bay. 



Genus LEUCOT1NA A. Adams, 1860. 



Leucotina A. AD., Ann. Mag. N. H. 1860, (3) v, p. 406, type 

 niphonensis. E. A. SMITH, Proc. Zool. Soc. Lond. 1890, p. 298.- 

 Myonia A. AD., Ann. Mag. Nat. Hist. (3), v, p. 406, type M.ja\ 

 ica. Not Myoma Dana, Amer. Journ. Sci., iv, p. 158, 1847.- 

 Monoptygrna A. AD., (in part) P. Z. S. 1851, p. 222, and in Sowb. 

 Thes. Conch, ii, p. 816. Not Monoptygma Lea. 



Shell ovate or elongated, usually rimate, thin, whitish, with coi 

 vex whorls; sculptured with spiral punctured or subpunct 

 grooves. Aperture rather small, oblong, produced and rounded b( 

 low, the outer lip simple or crenulated within, columella with om 

 small oblique fold. Type L. niphonensis A. Ad. 



