MARINE BIOLOGICAL STATION AT PORT ERIN. 



85 



In the upper one it is forming the outer coating, and 

 in the lower the branched sandy filaments which surround 

 the mouth of the tube, whilst some of the figures shew how 

 the delicate tentacles capture and convey the sand grains, 

 or building material. 



The right-hand lower figure shews the complete 

 structure. Two curious pelagic or free-swimming worms 

 are shown in fig. XII., viz., Sagitta bijjunctata at 2, and 

 Tomojrteris oniscif ormis at 4. 



POLYZOA 



(Fig. XL) 



On sea-weeds and under stones on the shore there are 

 many beautiful little colonies of worm-like animals to be 

 found, which, from their compound condition, are called 



Fig. XI. 



Polyzoa. Some are erect branched colonies (see fig. XI., 

 1 and 4) like Zoophytes, from which they can only be 

 distinguished by the microscope ; others are flat and 



