MOSS-ANIMALS. 



421 



paratively conspicuous ; but we might have chosen any other of the many beautiful 

 but less conspicuous forms. On any sea-coast a harvest of them can be gathered 

 in a few days. Certain species are almost always to be found on nearly every 

 leafy seaweed, and where the bottom of the sea is favourable, stones and the 

 shells of molluscs, both full and empty, are covered with stocks of Bryozoa, often 

 only discoverable by means of careful examination with a magnifying glasa 



Owing to the . . 



hardening and 

 frequent calcifica- 

 tion of the greater 

 part of the body- 

 wall to ^orm the 

 cell into which 

 the anterior part 

 that always re- 

 mains soft can be 

 withdrawn, these 

 animals are often 

 found as fossils. 

 The marvellous 

 variety of forms 

 presented by these 

 delicate little 

 stocks is in each 

 case determined 

 by the particular 

 manner of bud- 

 ding. The first 

 animal which, by 

 budding, gives rise 

 to the stock is 

 produced from an 

 egg, and begins to 



bud as soon as it has become attached. In each family or species the buds appear 

 at special points, and assume definite positions with regard to the parent individual. 

 The smallest variation in this respect causes the profoundest changes in the forms 

 of the stocks produced. Their classification is determined principally by the 

 structure of the mouth and of the tentacle crown, as may best be gathered from a 

 few examples. We take first the subclass Ectoprocta. 



Order Most of the fresh -water moss -animals belong to the order 



Phyiactoi»mata.phyi ac t igg ma t a) so-called because the mouth is provided with a 

 tongue-shaped lid. The crown of tentacles, which is also a gill, is horseshoe- 

 shaped, and the whole surrounded at its base by an integument forming a kind of 

 calyx or cup. , The chambers or cells are either quite soft or else horny, and are 

 thus not found in a fossil condition. Later on in this volume is described a 

 colony of sea-anemones which, instead of being fixed, as are most stocks, are 



lace-cokal, or Neptune's sleeve, Retepora cellulosa (nat. size). 



