Ookinesis in ( Vivhnitnlns Laetcus. 383 



Whatever the function of rays may be, they are the expression 

 of an attraction toward the centre. Fig. (r2 (Ph IV) shows a case 

 in which the rays of the sperm ast(n* have jnilled the chromosomes 

 of the luaturatiou mitosis toward the centres (cf. Ilenneguy, '91, 

 p. 417, Fig. 17, or, '9G, p. 350). 



The spindle fibres are made u}) of hyalophism more highly modified 

 than that of pole rays. The spindle may be removed as a whole by the 

 currents and retains its entity even after the egg is crushed (Ziegler, 

 '95, p. 385 ; Mathews, '07, p. 90). In the degenerating eggs of Cere- 

 brat ulits (kept unfertilized for five or six hours) the spindle is found 

 without perceptible change, while the pole rays fade always earlic]'. 

 It is interesting to note that the rays of two asters, when they come 

 near, have a tendency to take the form of a spindle, as in the case 

 of the sheath rays. Figs. 03-65 (PL IV) show this relation very 

 well. In the last figure a well developed spindle is seen between 

 the two asters. Fig. 60 (PI. IV) shows a spindle between the sperm 

 aster and maturation aster; Fig. 67 (PI. IV) represents that between 

 two sperm asters. 



Crossing of the rays takes place not only between two asters con- 

 nected by a spindle but also between two separate asters. In Cere- 

 hratulus the rays of the degenerating egg aster and , those of the 

 sperm aster do not form a spindle, but invariably cross one another, 

 an accunuilation of granular })recipitation being present between 

 the asters (PI. IV, Fig. 09). In this case the crossing may be in- 

 terpreted as due to a non-simultaneous action of two asters and local 

 disturbance (Khumbler, '98, p. 547, '03, pp. 520-522). But this 

 explanation is far from satisfactory when one tries to apply it to 

 the ordinary case of the crossing at the metaphase, which is a con- 

 stant process and not an accidental one (Meves, '99, p. 524). 



The fountain figiire is found in the egg of Cerebratulus in three 

 places: (a) around the cleavage plane when the constriction is nearly 

 completed (Text Fig. C. 5 on p. 380) ; (b) in the sperm rays im- 

 mediately prior to the conjugation of the germ nuclei (PI. IV, 

 Fig. 68), and (c) in the polar rays of the blastomere cleavages at 

 a late anaphase and the teleophase (''Polfontain" Rhumbler) (Text 

 Fig. C. 3 and 4 on p. 380). The anti-spindle figure described by 



