292 FERNANDUS PAYNE 



been increased by the recent work of Carothers and Robertson 

 who have described an unequal pair among the autosomes, the 

 distribution of which is at random. 



a. The chromatoid body. Again some readers may suspect 

 that the body which I have described as a single unpaired 

 chromosome is a chromatoid body, similar to the one described 

 by Wilson ('12) in Pentatoma. Wilson's principal reason for 

 describing this body was to point out the danger of confusing 

 it with an accessory chromosome. My reason for describing it 

 here is to demonstrate that the single unpaired chromosome in 

 Gryllotalpa borealis is not a chromotoid body. A chromotoid 

 body is present, but it is not the structure which I described as 

 a single unpaired chromosome. I have not attempted to trace 

 the origin of the chromotoid body, but it appears as a deeply 

 staining spherical structure in the early growth period (plate 1, 

 B) . It lies in the cytoplasm, near or in contact with the nuclear 

 wall, and remains in this condition and appearance throughout 

 the entire growth period. When the first spermatocyte chromo- 

 somes are in metaphase, it may he in the metaphase plate (plate 

 4, A), at one end of the sp'ndle (plate 4, E), or entirely outside 

 the spindle (plate 4, B, C, D) At this time it usually stains 

 intensely, as in the growth period, but occasionally it may stain 

 and even look like a plasmosome (plate 4, D). When the cell 

 divides it passes into one of the two secondary spermatocytes 

 (plate 1, I). I have not followed it later than this stage, but it 

 seems to disappear, rather than to pass, along with the cyto- 

 plasm, into the tail of the spermatozoon. A structure resem- 

 bling this body is seen in the tail of the spermatozoon, but, as I 

 shall show later, it is another structure. Both the chromotoid 

 body and the single unpaired chromosome can be seen in plate 

 4, A to E. In this particular case there can be no danger of 

 confusing the two structures. 



B. Gryllotalpa vulgaris 



a. Introductory statement. Since my preliminary paper went 

 to press two short papers by Voi'nov (12 and 14) have ap- 

 peared, describing, in Gryllotalpa vulgaris Latr., an unequal pair 



