294 



THE FOEAMINIFEEA 



variably been got from the mud at the bottom 

 of shore pools of greater or less depth. Under 

 the influence of the sunlight the Diatoms and 

 other algte, which grow in the mud at the bottom 

 of such pools, often rise to the surface in patches. 

 These act as rafts and carry the Ehizopoda up 

 with them. Once up, the outspread pseudopodia 



Fig. 38. — Various Forms of Dipping Tubes. 



enable even the largest and heaviest forms got 

 in our district to float perfectly. I have seen 

 a shore pool at Holywell covered quite thickly 

 with Pohjduinella striatopunctata (the commonest 

 form in the Dee), its reddish-coloured sarcode 

 rendering it easy to distinguish on the surface of 

 the water.' 



