DIVISION OP COLLAR-CELLS OF CLATHEINA CORIAOEA. 619 



arising" from a basal granule which is connected Avith the 

 nucleus. At division the basal granules divide and each 

 gives off two flagella ; though they do not appear to control 

 the division of the nucleus in any way, nevertheless each basal 

 granule is connected with the dividing nucleus by two streaks, 

 giving an appearance very similar to that figured by us on 

 Plate 25, figs. 4 and 5. (Jahn also figures a very similar 

 condition.) Dobell (2), in his investigations on Tricho- 

 monas, etc., appears to support a view similar to our own. 

 Lastly, Yamamoto (21), who has studied the locomotor 

 apparatus of various organisms by methods which seem to us 

 unduly violent and severe, describes the flagellum of a trypa- 

 nosome as arising from a basal granule ("^ proximal centriole") ; 

 liis statements, in matters of fact, simply confirm those of 

 Schaudinn.^ 



Observations on the Division of the Collar- cells.^ 



The material on which this work was done consists of a 

 number of specimens of Clathrina coriacea preserved by 

 one of us at Roscoff, and embedded in paraffin at the time. 



1 Yamamoto states that he has obtained preparations of trypanosomes 

 (sj)ecies not stated) showing myonenie fibrillse, of which he states I 

 deny the existence. This is a glaring misstatement on his part, seeing 

 that I have described and figured tlie myonemes of Trypanosoma 

 percte and T. granulosum in full detail (vide ' Proc. Zool. Soc. 

 Lond.; 1909. pi. v, figs. 84. 96. 97).— E. A. M. 



- I greatly regret that in my account of the Sponges in Lankester's 

 • Treatise on Zoology ' (Part II, 1900, p. 56) I gave an entirely erroneous 

 account of the division of the collar-cells of Clathrina coriacea, 

 stating that after division of tlie nucleus the cell divides transversely 

 to its long axis, and then the basal portion forms a new collar and 

 flagellum. I have re-examined the figures and preparations on which 

 these statements were founded, and see that I was misled by sections 

 passing obliquely through the epithelium, so that the top part of a 

 dividing cell, with the nucleus at the apex, appeared superposed on the 

 base of an ordinary cell, with its nucleus in the usual position. The 

 account given in the present memoir will show clearly the error of my 

 former statements. — E. A. M. 



