3. THE INTEGUMENT AND ASSOCIATED STRUCTURES 41 



There are few flask-shaped glands in the coelom of the trunk in Athe- 

 canephria, except in the postannular region, where, in S. caulleryi for 

 example, the glands are situated in metameric groups of six in the region of 

 each dorsal glandular shield, onto whose surface they open (Figs. 14, 22). 



The anterior metameric papillae, moreover, house glands whose ducts 

 open onto the ventral or external surface of the papilla. In Spirobrachia, 

 Lamellisabella and Siboglinum caulleryi each papilla houses only one gland 

 (Fig. 33), but in other species there may be several glands in each papilla 

 (Figs. 9, 68). 



