126 KANSAS UNIVERSITY SCIENCE BULLETIN. 



In order that I might discover whether I was in error, I next 

 chose two cells, one of the primary spermatogonial and one of the 

 first spermatocyte as illustrated in Baumgartner's paper on Gryllus 

 domesticus. In the spermatogonia the diameter was .514,", but 

 not .83 ,", as Meek gives for the same material, and the lengths 

 range from .86 to 2.41 ,«, and not from .8 to 6.71 ,". In the first 

 spermatocyte the diameter of seven was .514 ,", that of one was 

 .69 ," and that of another was 1.04,", excluding the accessory; the 

 lengths ranging from 1.04 to 4.13,". 



SUMMARY. 



The number of chromosomes is twenty-four in the somatic 

 cells of the Ambystoma, agreeing with the number in the primary 

 spermatocyte. 



The chromosomes are grouped about the equatorial plate in a 

 U or V shape with the spindle fibres attached, one at the vertex 

 of each chromosome, so that the arms of the V are of unequal 

 length. 



They differ in size and form in different tissues, being thick 

 and rough in outline in some, and long, slender and smooth in 

 others. 



The chromosomes of the pigment cells are long and thin in 

 proportion to their length and possess higher staining qualities 

 than the others. 



It is impossible to arrange the chromosomes in any one cell in 

 any systematic classification according to form or size. 



There is a difference in chromosome diameter due to age and 

 there is a difference in different tissues of the same age, but this 

 variation is not constant. 



The diameter is not constant in all phases of the same tissue. 



The diameter is not constant for all the chromosomes in any 

 one somatic cell of any particular tissue. 



The diameters of the chromosomes in neuroplasm and ectoplasm 

 decrease as the age of the animal increases. 



The diameter and volume of the phyla are not constant, neither 

 do their lengths constitute an arithmetical series. 



The volumes range from 1.54 to 17.94 cu.," and in a single cell 

 the volume ranged from 2.84 to 5.63 cu.,". 



The germ cells may have several diameters which are identical 

 but they do not posses an absolutely constant diameter, nor do the 

 lengths form an arithmetical series. 



