92 H. J. VAN CLEAVE. 



probable that some change in the vitellarium may be induced by 

 or correlated with changes in the adjacent ovary. 



The glands which have 10 nuclei each seem to offer distinct 

 evidence that the additional nuclei have been derived by the divi- 

 sion of one nucleus from the anterior and one from the posterior 

 row of a normal individual (Figs. 7 and 8). If two nuclei of 

 each row in a normal individual were to undergo division 12 

 nuclei would result as is the case in one individual observed 



(Fig- 9)- 



NUCLEI OF THE GASTRIC GLANDS. 



Shull found 9 out of 120 gastric glands which he examined 

 carrying numbers of nuclei other than 6, the characteristic num- 

 ber. According to his records 7.5 per cent, of the glands fail to 

 support the idea of constancy in the numbers of nuclei. By us- 

 ing the same whole mounts described earlier in this paper the 

 writer has secured data on the nuclei of 435 gastric glands, not 

 a single one of which displayed any deviation from the 6 nuclei 

 characteristic for that organ. A comparison O'f the two sets of 

 data is clearly presented in the following table. 



TABLE II. 



FREQUENCY OF DIFFERENT NUMBERS OF NUCLEI OBSERVED IN THE GASTRIC 



GLANDS OF Hydatina scuta. 



Number of nuclei 4 5 6 



Times observed by Shull i 7 IJI I 



Times observed by Van Cleave o o 435 o 



According to Shull's statement (1918: 463) all of the various 

 conditions of culture medium, age, and male or female produc- 

 ing strains seem to produce aberrant numbers of gastric gland 

 nuclei. In the case of male producers he examined only 36 in- 

 dividuals and found none with aberrant numbers of nuclei, but 

 also mentioned the fact that in view of the small numbers ex- 

 amined this circumstance may be insignificant. 



CONCLUSIONS. 



Referring to the solution of the problem of cell-constancy, 

 Shull (1918: 464) has said: "there is no need of complicating 



