188 CALIFORNIA ACADEMY OF SCIENCES 



Class gastropoda; 



Order OPISTHOBRANCHIATA. 



Family XLI. ACT^ONIDiE. 



Genus Actseon Montfort. 



Shell solid, ovate, with a conical, many-whorled spire, spirally grooved or punctate-striate; 

 aperture long, narrow, rounded in front; outer lip sharp; columella with a strong, tortuous fold. 



Ihrnatella fasciata Lam. is a characteristic species. 

 144. Actaeon traskii Stearns. 



Plate X, Fio. 6. 



Act(eo7i /ra^/^zV Stearns, Nautilus, Vol. XI, 1S97, p. 14; Proc. U. S. Nat. Mus., Vol. XXI, 1899, 

 p. 297, text-fig. 



Shell small, conical above, cylindrical, rather solid; sculpture consisting of numerous fine, 

 spiral, impressed lines, which become wider toward the base of the body-whorl, making the lower 

 portion of the shell lirate, and by sharp, close-set, incremental lines; these latter are subordinate to 

 the spiral sculpture; whorls six; suture distinct, narrowly channeled; aperture about two-thirds 

 length of the shell, acutely angular above, rounded and effuse below, finely lirate and glossy within, 

 with a thin glazing on the body-whorl; outer lip thin, simple; columella short and flexuous, with a 

 conspicuous fold curving around the same and thickening the edge of the lip, which is moderately 

 produced in the umbilical region. 



Dimensions. — Long. 10 mm.; lat. 5.2 mm.; body-whorl 8.3 mm. aperture 7 mm. 



Distinguishable from Rictaxis pundocctlata by its larger size, more impressed 

 suttire, more cylindrical body-whorl, more prominent and effuse anterior plication. 

 Specimens identified by Dr. Dall. Rare in upper San Pedro series of San Pedro. 



Found in the Pleistocene at Spanish Bight, from which locality it was 

 originally described. The specimen figured is from the upper San Pedro series at 

 San Pedro, and is now in the collection of Delos Arnold. 



? Living — San Diego (Stearns). 



Pleistocene. — San Pedro (Arnold): San Diego (Stearns; Hamlin; Arnold). 



Subgenus Rictaxis Dall. 



Shell);like AcicBon, but with the columella projecting beyond the line of the anterior margin, 

 forming a small, tooth-like projection, or truncate obliquely. 



Type, Tornatdla punctoccBlata Cpr. 



' Tho cl,i«Rlflcatlou of the Gastropod! I9 that used by Dall In Parts I and II of the " Contributions to the Tertiary Fauna of 

 Florida." and In Bulletin No. 37, United States National Museum. The generic descriptions are for the most part from Tryou's " Struc- 

 tural and Systematic Conchology." 



