282 



POLYCHAETA 



Reduced from 



from the anterior region after the formation of a new 

 between the two regions. 1 



Another modification of the process of budding and fission 

 is exhibited by Syllis ramosa, one of the most interesting forms 

 of animal life which was obtained by the " Challenger." This 



worm consists 



of a main stem, 

 whence arise a 

 number of lateral 

 branches, which 

 may also branch 

 so as to give rise 

 to an arborescent 

 colony (Fig. 150). 

 The branches of 

 the first and second 

 and higher orders 

 arise by budding 

 from the sides of 

 and some of these 

 branches develop generative products, and bud forth a head 

 near the point of attachment. These sexual branches, no doubt, 

 separate from the colony and distribute the ova. The worm 

 lives in a Hexactinellid sponge, Crateromorpha meyeri, living in 

 depths of 95 to 140 fathoms in the Eastern seas. 2 



Regeneration of lost Parts. The process of budding and 

 fission of the worm into two parts is merely an extension of that 

 resulting; in the formation of new segments when the worm is 

 injured. In most of the Nereidiform Polychaetes the number of 

 segments forming the body continues to increase throughout life 

 by the formation of new segments between the anal segment and 

 the one in front of it ; that is to say, there is normally a process 

 of budding taking place at this point. Now in many of the 

 longer worms it may be noticed that the segments of the hinder 

 end suddenly become smaller than the rest ; these are segments 

 newly formed to replace those lost by the worm. But this 

 " regeneration," though the same in principle as ordinary growth 



-Portion of Syllis ramosa. 

 M'Intosh. ) 



the original form or branches of lower order 



1 Huxley, Edinb. New Philosoph. Journ. 1855, i. p. 113. 



2 "Challenger" Reports, vol. xii. 1885, " Polychaeta, " p. 198 

 Centralbl. ii. 1895, p. 591. 



and Oka, Zoolog. 



