474 



ANNELIDA. 



mentioned. The larva of Lopadorliynclius (Kleinenberg) is of this 



type, but its embry- 

 onic development is 

 unfortunately not 

 known. 



In the larvae 

 cilia are rarely dis- 

 tributed over the 

 whole surface of 

 the body (Atrocha,* 

 Fig. 378). They 

 are usually confined 

 to special rings. 

 Sometimes, as in 

 Loven's larva, there 

 is one row placed 

 in front of the 

 mouth at some dis- 

 tance from the an- 

 terior end of the 



FIG. 380. Larvae of Polyeltaeta (after Busch.). o, larva of Nereis. 

 F tentacle ; Oc eyes ; PrW preoral ring ; mouth ; A anus. 

 6, mesotrochal larva of Chactopterus ; li'p circles of cilia. 



body (e.g., larva of Potynoe, etc.). Sometimes there are two rows, 



FIG. 381. Lateral view of Mitraria larvae (after Metschnikoff, from Balfour). an anus ; 

 6 and Ir the processes carrying the provisional setae ; m mouth ; pr.b preoral ring ; sg apical 

 plate. 



* Of. E. Claparede and E. Metschnikoff, " Beitriige zur Entwickelungsgesch. 

 der Chaetopoden," Z.f. w. Z., 19, 1869. 



