(45) 

 their homolo£;ues. "The atrial j^roovea" o i' t i.e Ac finotrccha, 

 he saya, no..?v-.-, are the r.nalOt^tics u^ ^.i! 1-slito. (15-page 319) 

 On par.e o5C (15), however, ho says tiiat "tentatively, 1 v/ould 

 regard the atrial grooves of the Actinotroci:a as t);e early rudi- 

 ments of phar:/ngeal clefts as found in Cephaloaiscus" . 



His "oral grooves", he says, corresj^ond with t lie oral 

 grooves in CephalodisciJ s. 



Resile (20) aoes not fina tne "atrial grooves" but finds 

 t'.vo lateral grooves which he considers to be fonried by the in- 

 sertion of the hood Oil to tno collbir wall. 



Ikeda (9) ana Lcn^champs (12) are of ti:a opixiioii th^at these 

 grooves do not norx:ially exist, 



I have L'laac a careful stuay of tr.o live Ac tine t •"ociia and 

 of surface moiuits but have .^ot Loen able to make out tneae 

 grooves in either Species, A., or Species, B. Sections, how- 



over, siiow that the "oral grooves" are present aijd that in most 

 i- reparations v;here tie preoral hood has been turned upward by 



violent contraction (due to tne fixin_ agent) theru are two 



in 

 snort grooves in the po sition, which Masteraaji +'inds the "atrial 



grooves". ju tnose cases in which the hcca rerriains in its no r- 



r.ial position I havo seldom fuuna Masterman's so-called "atrial 



grooves" uiid even in a fev; cases where tne hooa is tu-ned upwara 



they have been absent. 



