DIVISION OP COLLAR-CELLS OF CLATHRINA CORIACEA. 633 



the same body functions at one and the same time as a 

 blepharoplast and a centrosome, thus furnishing a decisive 

 proof of the identical nature of these bodies, at least in the 

 class of cells that we have been studying. 



We are therefore in entire agreement with those authors 

 who regard blepharoplasts as bodies of centrosomic nature. 

 It is very obvious in the case which we have studied that the 

 terms " blepharoplast " and ''centrosome" denote merely two 

 different functional activities of the same body. It may well 

 be that in other cases division of labour may lead to structural 

 differentiation, and that two distinct and independent classes 

 of bodies occur, centrosomes conti-oUing nuclear division and 

 blepharoplasts giving rise to locomotor cell-organs. But in 

 all cases alike we regard centrosomes and blepharoplasts as 

 organs similar in nature and identical in phyletic origin. 



It only remains to discuss how far the results we have 

 obtained throw light on the state of things in other cases, 

 and more particularly with regard to the vexed question of 

 the true blepharoplast in trypanosomes, that is to say, whether 

 thename ''blepharoplast" should be given to the kinetonucleus, 

 or to the basal granule of the flagellum in these organisms. 

 With regard to this point, it may be stated at once that 

 there is nothing whatever in the structure or behaviour of 

 the centrosome-blepharoplast of the collar-cells to justify a 

 comparison between it and the kinetonucleus of a trypano- 

 some, or, indeed, a nucleus of any kind. We are fully in 

 agreement with those who, following Schaudinn, regard the 

 kinetonucleus of trypanosomes as a body of the nature of a 

 nucleus, and it is precisely on this ground that we regard it 

 as a body of a different nature from a true blepharoplast, 

 such as that which is seen in the collar-cells, and which 

 cannot, in our opinion, be identified as a nucleus by any 

 stretch of the imagination. On the other hand, the body, 

 which in a trypanosome corresponds in every way to the 

 ti'ue blepharoplast, is the basal granule or centriole of the 

 flagellum. 



Our position, therefore, with regard to the nuclear apparatus 



