SPIRULA. 



517 



tucket. The shell is white and j)carly, coiled u\) in two ^'s- "^• 

 or three turns, which do not touch each other, some- 

 thing like a ram's horn. The surface exhibits constric- 

 tions, at short intervals, each of which corresponds to 

 an internal partition, so that the whole shell is divided 

 ofif into chambers, having a tube, however, at one side, so that the 

 whole are in communication. ( Gould.) 



The specimen figured is from the cabinet of E. R. Mayo, Esq. 

 It is from Nantucket. 



S./ragiUs. 



