(76) 

 blood corpuscles were not present. 



Actiriotrocha Species, A. with 16 tentacles invarj ably has 

 blooa corrus.cles and they are present in the so-called collar 

 cavity as tv/o i^.asses more or less closely api-liea to tne ventro- 

 lateral walls of the stoinach. ( "Fi^^o. 51 (^J - (h) ) In some c<a.- 

 ses, he ■■.•over, they are t,*^ puratea from t^ie v:all by a considerable 

 space. 



The transverse section of a larva with IL ter.tacles in a 

 plane j"^t :c..torior to tne base o f the tentacles but cAiiteriO'" 

 to the mesenter;'^ a.lv;ays shows two masses of cells bilaterally 

 plucea ca^a closely applied t. t.a'^ m:o„acn:n lining, the ventro- 

 lateral somatic v/all. ( ^i ^ . oo ) Occasionally 1 have founa cells 

 in these masses situatea very close to the mesodenral linin., 

 which "-ere uecidedly spinale-shapeu in form and v.'hc ^e nuclei re- 

 sembled 1-hcse of the cells o *' the mesodermal linint^, both in 

 sha^e, size aiia internal structure. These cells are -uo t very 

 rich in cytoplasm, Most o "^' th.e cells, hov/ever, are almost 

 tiiree times the size o f the cells linint^ the somatic wall, the 

 cytoplasmic part of the cell havin,-, increaseu in size to a f^reat- 

 er extent thari the nucleus, Iv'ost of the nuclei have large deep- 

 ly stainint, nucleoli. i'^^^t.-^^^) 



In some specimens, parts o "^ these masses of cells are appar- 

 ently in the act of wand"Hn^ across the body cavity lo the posi- 



