148 



FERNANDUS PAYNE. 



the physical basis of certain forms of correlation in heredity. 

 The suggestion seems a very plausible one for the above cases, 

 but the complex in Acholla is somewhat different. All three 

 chromosomes are univalent and divide in the first division. In 

 the second division the group separates, the large chromosome 

 passing to one pole and the other two to the opposite pole. 



Acholla anipliata Stal. 



Acholla innfliata appears to be the species which Montgomery 

 Co i and '06) describes under the name of " Acholla multi- 

 spinosa." He figures the spermatogonial division with 32 chro- 

 mosomes, eight of which are very small, and both the first and 

 second divisions with 16 chromosomes, four of which are small. 

 In the first division, the four small ones may lie in any position, 

 but in the second division, they are centrally placed and grouped 

 closely together. Unfortunately my material shows only the 

 first and second divisions which agree with those, which Mont- 

 gomery figures, except that in the second division, the small ones 

 are grouped so closely together that it is impossible to distinguish 



D E F 



FIG. ii. Acholla anipliata Stal. A and B, metaphase figures of the first 

 division, 16 chromosomes; C and D, metaphase figures of the second division 

 there are 12 chromosomes in the ring and the small ones are grouped in the 

 center so that it is impossible to count them ; E, typical appearance of the 

 nucleus during the later part of the growth period the four small chromo- 

 somes are embedded in the plasmosome ; F, prophase of the first division 

 the plasmosome has disappeared, but the four small chromosomes remain. 

 The enlargement is 4,018 diameters. 



