244 ARTHUR WILLEY. 



oral lobe (p. 315) the authors say, " Chez les Tuniciers 

 adultes, il n'existe rien de tel, mais chez leur larve on retrouve 

 des dispositions tout a fait comparables a celles de TAm- 

 phioxus." 



I have been treated to harsh words for holding the view that 

 the organ of fixation of the Ascidian larva represents the prse- 

 oral lobe. It is therefore possibly a matter for satisfaction 

 that this view finds favour with the authors, but I could have 

 wished that they had been more explicit. It may be worth 

 while to add, in order to ward off possible misunderstanding, 

 that for my own part I am more than ever convinced of its 

 essential truth. 



Klaatsch (loc. cit.) has recently made the suggestion 

 " mit allem Vorbehalt," " dass das holbenfdrmige Driise [club- 

 shaped gland of the larva of Amphioxus] die Anlage des Ten- 

 takelskelets darslellen konnte." 



This is an astounding suggestion to make, and it will not 

 survive criticism. The skeletal elements of the buccal cirri 

 commence to appear long before the disintegration and conse- 

 quent disappearance of the club-shaped gland.^ 



' I venture to refer Dr, Klaatsch to my paper entitled " Tlie Later Larval 

 Development of Ampbioxus," ' Quart. Journ. Micr. Sci.,' vol. 32, 1891; and 

 to the figures on PI. 15 accompanying the paper. He may there see for 

 himself the vindication of what I have said above. If he doubts the accuracy 

 of these figures, possibly in his next publication he will kindly inform us why 

 he does so. 



