CLASS PELECYPODA 
203 
Corbula fragilis Hinds, 1843. 
Proc. Zool. Soc., p. 56. Zool. Sulphur Voy., Moll., p. 68; pi. 20, fig. 11. 
Shell ovately diamond-shaped, thin, semi-transparent, white, longi¬ 
tudinally striated, striae raised, numerous, close-set, crossed with exceeding 
fine lines radiating from the umbos; anterior side angularly produced; 
umbos rather depressed, straightly incurved. (Conch. Iconica.) 
Type in Museum Belcher. Type locality, Veragua, Mexico. 
Range. Monterey, California, to Magdalena Bay, Lower California. 
Corbula luteola Carpenter, 1865. 
Sup pi. Brit. Assoc. Rep., p. 673. Arnold, Pal. San Pedro, pi. 17, fig. 11. 
C. t. “C. biradiata,” forma simulante, sed multo minore; haud obesa, 
transversa, luteo-cinera, dorsum versum interdum obscure biradiata; 
angulo plus minusve carinato, postice definato ; antice rotundata, expansa; 
concentrice crebre sed obtuse lirulata; umbonibus obtusis; intus, dentibus 
minoribus; linea pallii angulata, haud sinuata; cicatricibus adductoribus 
callosis; margine t. adulta postice altero alterum amplectante. (Carpenter.) 
Shell small, sub-elliptical, gibbous, thick; beaks sub-central, small, 
inconspicuous; anterior extremity evenly rounded; posterior dorsal margin 
slightly arcuate, sloping down nearly to base, where it turns abruptly, 
forming an angular extremity; ventral margin arcuated, a sharp sub- 
marginal ridge extends from beak to lower portion of posterior extremity; 
surface sculptured with fine, but distant, concentric ridges; right valve 
with one prominent cardinal tooth in front of cartilage pit; left valve 
smaller, with a projecting cartilage process; pallial sinus slight; pedal 
scar distinct from adductor impression. (Arnold.) 
Type locality, San Pedro or San Diego, California. 
Range. Monterey, California, to Lower California. In the Pleisto¬ 
cene at San Pedro and San Diego, and the Pliocene at San Pedro, Cali¬ 
fornia. 
Corbula luteola rosea Williamson, 1905. 
Proc. Southern Cal. Acad. Set., 4:120. 
Shell same as the typical, but the disk of this variety is of a bright 
pink, excepting a ray of white from the beak across the umbonal portion; 
around the hinge area and the ventral margin the color is of a rosy flesh 
color; the interior of the valve is pink. (Williamson.) 
Type in the Williamson Collection, Los Angeles Museum, Expositon 
Park. Type locality, Terminal Island, San Pedro, California. 
Range. The same as the typical. A color form. 
