Fig. 3. — Various unusual types of spindles, a = the spindle 

 at the first meiotic division in the scale insect Llaveia 

 houvari '° where the spindle elements are quite separate. 

 6 = a tripolar spindle at early anaphase, c = the half- 

 spindle formed at the first meiotic division in the fly 

 Sciara cojyrophila.'^^* d = a. late anaphase spindle in 

 a hybrid where the central region has undergone great 

 elongation.*^ In c all the maternal chromosomes 

 (including the two ' limited ' ones L and L') go to the 

 pole, the paternal ones (I^, 11^, III^ and IV^ in order 

 of size) moving in the opposite direction. 



