THE VERMETUS. 



143 



rated as distinct, under the name of TubuUbranchiatay 

 (having branchise in a tubular cavity.) The animals 

 of this group inhabit long irregular shells, spirally con- 

 torted, but without a definite figure ; and these shells, 

 as in the vermetus, are often twisted and interlocked 



Vermetus. 



with each other and with foreign substances. The 

 above sketch shows the character of the vermetus, 



