{Ok) 



of tke same. ( T-^igs. 44- (u) - (b) - ) Y^nere tr.e edt^e of tne hooa 



j.c(,cib:.o iiitu tri-^ wj.i.j. v^f tl-.c collar cavity tneae fibers are seen 

 to nni 01. tc the interiial surface of ti.e lateral wall of tl.e 

 collar ai-id to miiij_;le fi-ijally with the fibcrj ^f the aorsal tract. 

 The ciirectioii these fibers take v/hen they pass on to tr:e wall of 

 t!-e collar remivids otjC vorj much of the fibers \'.nicn Mastoraaii 

 (15) figi'rea as nerve fibers. 



On the interi.al ventral surface of tr.e hooa in bo ti^ species 

 of /^ctinotro Ciiae, there is a system of muscle fibers arranged 

 concentrically. They run almost parallel v;ith one another and 

 with the edre of the hood. (Fii_;s.47 and 44(a) ) 



Beside the tracts of muscle fibers v/hici-. 1 have described, 

 ti'.erp are, liniut, the walls of the collar and tnjniC, circular 

 muscle fibers lyin^; between the lon-itudinal muscle fibers ana 

 ti:e ectoderm. These have been t^enerally obse'-ved by previous 

 v.'orkers as have also the muscular coverinr of the ventral poucii 

 and the muscle cells of the dorsal blood vessels. 



Bo dy Cavi ties , Mesont en. e_s , e tc . ; - Muci; dif^^erence o-^ opinion 

 exicsta as to the orisiin and limits of the boay cavities in the 

 Actinct '"ccha and also as tc the value of these cavities in deter- 

 iniiiin^ tlie phylogenetic history of Phoronis, 



Roule (£0) stands aloTie in considerinr the Actinotrocna to 

 aave but one body cavity 'M:ich is lined by an epithelium formed 



