VERMES THE WORMS 103 



A larger species, of stouter build, being about the 

 thickness of an ordinary penholder, is Phalcolosoma elongata. 

 Allied to them is a larger, striated, and tubiculated form, 



Fig. 40 

 Chwtopterus variopedatus. f Natural size 



Sipunculus nudus, but this is much less common, and 

 occurs only at the lowest littoral zone. They have been 

 by most authorities placed with the worms on account 



