ASEXUAL KEPRODUC'lION. 



197 



in a panic, but a few are also known to do this in apparently normal life. 

 Each part — there may be more than two — reproduces the whole. Thus, at 

 a comparatively high level among animals, reproduction may be literally 

 rupture. Oftener, however, budding precedes the division, and curious 

 chains of ringed worms are thus produced. Nor do the budded individuals 

 always keep in a straight line, but, as in the freshwater naids, may abut at 

 angles, and form a quaint living branch. To what degrees this irregularity 

 of budding may attain is well seen in the accompanying cut of a portion of 

 a worm {Syllis ra//iosa), found on the " Challenger " voyage. The buds 

 occur laterally, terminally, or on any broken surface, and the result is an 

 almost bush-like compound organism rivalling even the hydroids in the 

 freedom of its branching. .Some of the branches become males or females, and 

 go separate, or are sent adrift. In other syllids, the separation of a series 



Comet form of a Starfish, showing how one arm " regenerates" or reproduces 

 otlier four. — From Carus Sterne, after Ha^ckel. 



of joints as a sexual individual has been repeatedly observed, or this may 

 be reduced till only one joint, laden with reproductive elements, is set free. 

 In many of these chxtopods the budding begins when the normal size of 

 the individual has been stopped by unfavourable conditions, which bring 

 about separation, and the sul;sequent sexuality of the liberated individuals. 



Adventitious buds forming at the sides of a \^vS oi BryopJiylluju 

 calycimuii. — From nature. 



Starfishes and the like surrender their "arms" so readily, that some 

 have supposed that they might, in this way, normally multiply. A 

 voluntary surrender of parts as a mode of multiplication is, however, 

 in this case difficult to prove. So while crustaceans, insects, spiders, 

 and molluscs may lose and regrow certain parts, no asexual multiplication 

 occurs. 



