THE NAUTILUS. 



O. CONCHAPHILA Carpenter, 1856. Mazatlan to Panama. This 

 prettily painted form seems likely to retain specific rank. 



0. CHILENSIS Philippi. Gulf of California to Chile. 



This is the large edible Gulf species, referred by Carpenter to 0. 

 virginica, which it much resembles except in wanting the purple 

 muscular impression. It has numerous synonyms. 0. retusa Reeve, 

 of the Hawaian Pliocene is also very similar. 



O. CHILOENSIS Sowerby, from southern Chile, is small, round, and 

 feebly plicate, but may be a degenerate variety of 0. chilensis. 



O. MULTISTRIATA Hanley, 184G. Gulf of California to Panama. 



Usually small and flat with brown and purple blotches on the 

 white inner surface. Easily identified by the sharp radial stria; of 

 the outer surface which is usually a purple tint. 



OSTREA TUBULIFERA Dall, n. Sp. 



The specimen serving as type for this species was collected in the 

 Gulf of California by Henry Edwards ; it is suborbicular, about 45 

 mm. in diameter, nearly flat, with a whitish nacre, brilliantly pol- 

 ished inside, purple clouds showing through, and with a translucent 

 irregularly crenulated margin. The ligamentary area is narrow and 

 very inconspicuous ; on each side of it the margin is pustulate for a 

 short distance ; the outer surface is mostly dark purple, dull, minutely 

 corrugated and densely covered with small erect tubules of a dark 

 reddish-brown color, 2 to 4 nim. high and from f to 1 mm. in diam- 

 eter. Only those at the extreme margin communicate with the 

 interior of the valves, and these are fissured on the distal side. 

 Those of the surface behind the margin are completely tubular. The 

 attached valve was not obtained. Several beachworn specimens 

 from Panama have lost their tubules and exhibit only a vermicularly 

 corrugated surface. The attached valve is very flat and irregular 

 with a very wide but very short area. These specimens are of <* 

 faded purple, but are probably the same species as the valve from 

 the Gulf of California. The only species at all approaching this in 

 character is the 0. spinosa Quoy, which comes from a widely differ- 

 ent region, and has a very prominent, direct and produced ligament- 

 ary area. 



