CALYPTREA. 



13 



smooth ; summit sharp and erect^ whitish ; in- 

 ternal appendage oblique. W. 37. 4. 



C. EQUESTRis, Sub-orbicular, wrinkled, and 

 minutely striated longitudinally ; summit lateral 

 and obtuse, white; margin sinuated irregularly. 

 1. w. 37. 1. 



C. RADIANS. Orbicular-depressed, trochi- 

 form, whitish or yellowish, adorned with sub- 

 nodulous, distant, rayed and elevated striae ; be- 

 neath concave, whitish, or spotted with brown, 

 with a spiral plate ; summit sub-central ; epider- 

 mis lamellar and brown. Size sometimes very 

 large. W. 37- 7- 



C. spiNOSA. Base ovate-roundish, conic, lon- 

 gitudinally wrinkled, with super-imposed tubular 

 spines, dirty brown ; interior rich coffee-brown, 

 except the borders of the cup ; diameter an inch . 



C. iMBRiCATA. Whitish, thick, sub-conic, 

 and ovate, imbricated by longitudinal ribs and 



