18 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Sek. 



6. A New Lepidozona From Southern California 



For several years past various specimens have been ac- 

 cumulating in my hands which do not seem" referable to 

 any of the described species. Some of these, particularly 

 from among the Mopaliidce, I shall withhold for the present 

 in the hope of securing more or better material, but there 

 are certain ones of which I either have had ample material, 

 or else see no immediate hope of getting more, or which are 

 likely to be referred to in forthcoming papers of this series, 

 hence must needs be published. A preliminary diagnosis of 

 one of these forms is therefore offered in the following pages, 

 while others will be published in succeeding papers of the 

 series. These descriptions are purposely made as brief as 

 the exigencies of an exact identification of the species referred 

 to will permit. The results of my examination of the radula, 

 the microscopy of the girdle armature, and some other fea- 

 tures are held over for a later work, in which it is intended 

 to describe, illustrate, and discuss all the western North 

 American species in as much detail as possible. 



Ischnochiton (Lepidozona) asthenes Berry 1919 

 (PI. 8) 



Diagnosis: Shell small, thin, nearly lusterless, oblong-oval, 

 moderately elevated, carinate along the ridge, the side slopes 

 convex; valves barely beaked behind. General surface 

 strongly rough-scaly-granulose. this condition prevailing over 

 the head valve, the lateral and jugal areas of the intermediate 

 valves, and the jugal and posterior areas of the tail valve; on 

 the pleural areas obscured or replaced by the fine sculpturing. 



Anterior valve with 11 or rarely 12 low, broad, rounded 

 ribs or flutings. bearing traces of radial series of minute, 

 easily abraded pustules, 2-4 in a series, though in absolutely 

 non-abraded specimens there would no doubt be a few more; 

 grooves between ribs shallow and narrow, but fairly distinct. 



Intermediate valves with lateral areas distinctly raised and 

 strongly radically bicostate^ the ribs broad, flattened, or the 

 center of each even somewhat obsoletely grooved, their dividing 



^ The lateral areas are apparently rarely tricostate, as witnessed by the second 

 valve of one of the specimens. 



