474 



ANNELIDA. 



mentioned. The larva of Lopadorhynchus (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 



FIG. 380. Larvae of PolycJiaeta (after Busch.). a, larva of berets. mouth at some dis- 

 F tentacle ; Oc eyes ; PrW preoral ring ; mouth ; A anus. tance from the an- 

 b, mesotrochal larva of Chaetopterus ; Wp circles of cilia. 



terior end of the 

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



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

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

 plate. 



* Cf. E. Claparede and E. Metschnikoff, " Beitrage zur Entwickelungsgesch. 

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



