(59) 

 in Species, A. They r.ave their origin at tl;e base of tue lar- 

 val tentacles but they are separate from them ar^ tney appear 

 first in the larva with 2A tentacles. 



This Actinotrocha ai ffers in three important respects from 

 Actinotrocha Species, A. In the -first place it i:as its blooa 

 corpuscles aggregated into four masses, tvio of v;hicu are usually 

 in the sar/iC position as the pair in the smaller species. The 

 other two, however, are fouvia, as a rule, more aiiteriorly in 

 the collar cavity ana are api-lisl to the oiorso -lat eral walls 

 of the stomach. The posterior pair lying on the vent ro-later- 

 al sides of tiie stomach make their appearance iuriiig the 16 or 

 kO tentacle stage but the other pair do not appear until about 

 Lhe 22 tentacle stage. 



This larva also has retractors exteviding from the ganglion 

 to the region of the first and second pair oT tentacles. 



A second point of difference is the fact that Actinotrocha 

 Species, E., possesses a pair o ^^ aiverticulae at the aiitorior 

 end of the stomach. These T founa to be present as early as 

 the 22 tentacle sta-.o. 



This larva cari further be aistinguishea from t'.e other spe- 

 cies by the fact that there is tbund in the older larvaea seii- 

 30 ry papilla on the irda-aorsal surface of the preoral lobe. 



Actinotrocha Species, E., is much more active v.hen irritatea 



