ABNORMAL MITOSES IN SPERMATOGENESIS. 1 87 



isolated ones. In this particular instance all the cells of an entire 

 cyst (male) contained the double number of chromosomes, which 

 were readily counted, as the cells were just concluding the first 

 spermatocyte division. This case presents one important point 

 of difference from all other examples of abnormal division in that 

 " the chromosomes are only half as large as are those at the cor- 

 responding stage of the normal spermatocyte stage " a very 

 unusual abnormality indeed. 



In the material which I have examined two instances of ab- 

 nonral chromosome number have been found which resemble the 

 one described by Morgan in that large numbers of cells are af- 

 fected, but the chromosomes are not reduced in size. A descrip- 

 tion of these cases will now be given. 



The first, and in some ways the less interesting, of these cases 

 was found in a specimen of Lo.va florida Van D. (Family Pcnta- 

 touiidcc}, of which both testes were affected in exactly the same 

 way and to the same extent. This particular abnormality was 

 restricted to a single lobe of the testis which happens to be com- 

 posed of cells of an unusually small size (see Bowen '22). i The 

 earlier stages in the affected lobe seem to be normal in every way 

 (Fig. 4), but with the inauguration of the growth period of the 

 primary spermatocytes a very unusual phenomenon sets in. 

 Large numbers ( but not all ) of the cells in each cyst fuse together 

 in pairs to form giant, bi-nucleate cells (Fig. 5). The cytoplas- 

 mic masses of the two cells seem to fuse completely, but the nuclei 

 remain separate although they frequently become so closely ap- 

 pressed as to show little visible separation. As the growth period 

 proceeds, this process of fusion goes on progressively, though 

 somewhat irregularly, with the result that eventually the prophase 

 cysts contain a heterogeneous mass of cells possessing in indi- 

 vidual cases anywhere from one to eight or more nuclei (Fig. 6), 

 each with its own complement of chromosomes. 2 The cells round 

 out and become somewhat separated from each other, those con- 

 taining numerous nuclei being roughly spherical in shape and of 



1 I have been able to examine only a single specimen of this speciei'. 

 It would be interesting to find out whether this abnormality has any relation 

 to the sizes of the cells which might possibly cause its production repeatedly. 



2 In Lo.va the spindle of the first spermatocyte division normally has eight 

 chromosomes, as in a number of other pentatomids (e-g., Eitschistus). 



