SEA "FIRS 



1071 



'—/i 



Muro-ffltotof^raph by Fi 



3. PLUMULAKIA PIN NAT A. 



MAGNIFIED PORTION OF SEA "FIR." 



form is preserved ; the second shows 

 a dried colony in which the sickle shape 

 assumed by the branches when dry can be 

 seen. These colonies sometimes grow 

 to about a foot in length, and are often 

 mistaken for seaweeds. 



On placing a colony, taken from the 

 rock-pool, in your 

 collecting jar filled 

 with sea water, the 

 little zooids will soon 

 come out of their 

 hiding-places in the 

 horny z o o i d-c u p s ; 

 and you will be able, 

 with the aid of 3'our 

 pocket lens, to make 

 out certain facts 

 about them, e.g. as to 

 how they feed, and 

 as to how they save 

 themselves from 

 being fed on. 



For as you look 

 you will learn that 

 they are doubly 

 equipped ; they have 

 arms of attack — their 

 many tentacles ; and, 

 better off than your- 

 self, their " skeleton " 

 is their castle. 



With their ten- 

 tacles, fine as they 



4. AMLS.MjLAklA ASIESSIA 



are, they catch their prey, and the sting- 

 ing cells with which they are provided 

 paralyse their unhappy victims. The same 

 thing happens with the fresh-water Hydra 

 Viridis, which " plays " its capture like 

 some skilful angler ; but, ev'en should the 

 prey be immediately released, it invariably 

 dies from the stings 

 inflicted. In the illus- 

 tration on this page 

 these tentacles are 

 shown in a greatly 

 magnified colony of 

 Pluniiilaria pinnata. 



The "skeleton," as 

 it is called, of the 

 whole colony consists 

 of the same horny 

 protective matter as 

 the individual zooid- 

 cups. The " feeding 

 tube," to which refer- 

 ence is made below, 

 is surrounded by it. 

 For life is a struggle 

 and a conflict even in 

 these lowest grades; 

 and while hungry 

 enemies are out on 

 the search for food, 

 our tinv zooids would 

 be snapped up as 

 unconsidered trifles, 

 were it not for the 



