132 



HARDWICKE'S SCIENCE-GOSSIP. 



as the polyp. They never occur in a separate or 

 naked form, as some hydroids do, but are always in 

 a polypidom or cell, which is either calcareous or 

 membranous. The tentacles of the polyp are ciliated, 

 by means of which particles of food are drawn into 

 the mouth. The stomach and a narrow intestinal 



rocks, facing the full force of the waves, we discover 

 a colony of tiny rose-coloured creatures, no larger 

 than the head of a pin ; this is the Clava miilticornis, 

 an uncovered hydroid zoophyte, somewhat club- 

 headed, and having about twenty-five tentacula. 

 At certain seasons a mass of ovarian capsules are 



Fig. Jo. — Lao7ncdea gcniciilaia. The small figure shows 

 the nat. size. 



Fig. Si. — Caittfiamilarta 

 geiiicnlata. The small 

 figure shows the nat. size. 



canal are developed in polyzoan forms ; there is no 

 organ of sense, though the polyps are sensible of 

 external impressions. Left undisturbed in still water, 

 the polyps protrude and disport themselves freely, 

 but if the water is shaken, the animal instantly retires, 

 remaining hidden from view for some minutes. If one 

 polyp is suddenly touched with a sharp instrument 

 it retires, the rest taking no notice, apparently un- 

 conscious that anything has happened. 



Starting at half-tide, as the waters ebb, we can 

 get to work within five minutes among the Ventnor 

 rocks with the certainty of being richly rewarded 

 after two hours' search. On the edge of greensand 



Fig. 82. — Laomcdea gelatiiiosa. The small figure 

 shows the nat. size. 



Fig. 83. — Phanidaria obliqua. 

 The small figure shows the nat. 

 size. 



grouped at the base of the tentacles. Placed in a 

 sea-water trough, such as can be purchased for one 

 shilling from Mr. Bolton, 17 Ann Street, Birmingham, 

 the clava, and indeed most other zoophytes, make 

 beautiful objects for microscopic observation. The 

 Ilydraciina echinata we found on a fusus thrown out 



