THE TOWER SHELL. 73 



In Fig, 58; we have a picture of the Tower Shell, 

 Tiirritella Cooperi^ Cpr. , Tur-ri-teF-la Coop'- 

 er-i, which is likewise a southern shell, found, 

 according to Mr. Hemphill, on the sandy 

 beach, between tides. The shell can hardly 

 be said to have a body-whorl, but consists 

 wholly of a slender, tapering, many-whorled 

 spire. The sutures are distinct, the aperture 

 circular, and the outer lip sharp and thin. 

 The color is yellowish, somewhat spotted with 

 brown; length, two inches. It can hardly be 

 mistaken for any other shell. 



Mesalia temiisailpta^ Cpr., Me-sa^-li-a ten- 

 ui-sculp'-ta, is like a minute specimen of the last, and 

 is found on mud flats. Its whorls are rounded, and 

 feebly sculptured by cross-lines. The usual length 

 is less than one-fourth of an inch. 



The next species is wholly different from any that 

 have gone before. It has a shell about one-eighth of 

 an inch long, looking like a minute, slightly- curv^ed 

 tube. Under the microscope it is seen to be com- 

 posed of very numerous and closely-crowded rings. 

 Its color is white or yellowish, and its name is CcEcit7n 

 CaliforniciLm^ Dall., Se'-kum Cal-i-for^-ni-cum. 



CcBcum crebricinctum^ Cpr., kre-bri-sink'-tum, is a 

 species having a shell twice as large as the last, 

 marked by exceedingly fine rings, which are often 

 quite indistinct. Both of these species are found 

 chiefly in the South. 



SpiroglypJms lititella^ Morch., Spi-ro-gly'-fus lit-u- 

 eFla. This singular mollusk has an irregular, tubular 

 shell, which becomes attached to the side of a stone, 

 and twists itself into an ill-shaped, flattened cone. 



