152 



cular, nearly flat, concentrically wrinkled, slightly con- 

 vex, with a small pointed apex near its centre; margin 

 very acute andsinuated; color generally a yellowish 

 white; interior surface more or less concave, finely stri- 

 ated, with raised spots or granulations, the centre part 

 with a dark chesnut-colored mark, and surrounded by 

 a smooth border. Lamarck mentions a second species 

 not having radiating striae on its under surface. These 

 shells sometimes attain several inches in diameter, and 

 some examples possess an epidermis, which circum- 

 stance is not mentioned by de Blainville, from whose 

 examination of this genus the above description has 

 been given. 



Umbrella Indica Umbrella Mediterranea. 



PARMOPHORUS 



PATELLA AMBIGUA, 



Chemnitz, 1 1, tab. 179, fig* 1918. 



De Blainville first pointed out the characteristic dis- 

 tinctions of this shell, which should be called Parmo- 

 phora. It is an oblong parallelogram, nearly flat; 

 posterior margin rounded, and rather wider than the 



