852 Transactions of the Society. 



for investigation ; above all, it will be necessary to cut specimens 

 that are in process of fission in order to ascertain the appearance 

 presented by the chambers in early development, v^hen probably 

 the confused image of the fully developed state will become com- 

 prehensible. The condition of the spine is seen in the photograph ; 

 it has a distinct cavity with an air-bubble ; but no opening exists as 

 far as I can determine. The continuation looks something like the 

 spines, stiff hairs, &c., of insects, which, as is well known, have no 

 opening at the end. 



