8o THE HAMILTON ASSOCIATION, 



of the mantle cements to the growing edges of the shells the peb- 

 bles and minute mollusca found attached. The writer was informed 

 by a Conchologist some years ago, in the old country, that in no 

 instance did these closely related shells appropriate for conveyance 

 or concealment their peculiar burthens. Why it should be so 

 appears to be one of the many mysteries of Nature. Ward gives 

 the shell a family name, Onustidce, and has seen tubes of Annelids, 

 a sponge, and cup coral attached to a Conchologist. He considers 

 Calyptrea fornicata, Atlantic coast, as a Bonnet also. 



