THE DIPLOID CHROMOSOME COMPLEXES OF THE PIG 189 



any in which an accurate count could be made — have shown 

 no tendency to a secondary or pseudo-reduction. Neither 

 have I, in the present study, seen any bodies comparable to the 

 X-chromosomes shown in Wodsedalek's figures. In poorly fixed 

 material obtained some years ago I have seen similar bodies. 

 This problem I hope to take up shortly. 



Other cytological work carried out on mammals includes 

 studies on man by Flemming ('98), Farmer and Moore ('05), 

 Moore and Arnold ('06), Duesberg ('06), Guyer ('10), Mont- 

 gomery ('12), Winiwarter ('12), Jordan ('14) and Wieman ('13 

 and '17). The diploid number as given by these workers varies 

 from 22 to 47 or 48. The rabbit is claimed to have chromosomes 

 ranging in number from 22 to 80. This form has been studied 

 by Flemming ('98), Winiwarter ('00), (who beheves that the 

 somatic number ranges from 42 to 80), Barratt ('07) and Bach- 

 huber ('16), Miss Stevens, in 1911, reported 56 chromosomes 

 for the guinea pig. Vom Rath, in 1894, found the somatic 

 chromosomes in the dog to range from 8 to 64, and pointed out 

 that the various numbers were always multiples of eight. Wini- 

 warter and Sainmont ('09) described 36 chromosomes for the 

 sex and somatic cells of the cat. In the opossum Jordan ('11), 

 found 17 chromosomes in both germ and somatic tissue. Schoen- 

 feld's work on the bull ('07) is largely a study of the prophase 

 behavior, and the number of chromosomes is not given. Wodse- 

 dalek found 37 chromosomes in the horse ('14) and 51 chromo- 

 somes in the mule ('16). Yocum ('17) has reported 20 chromo- 

 somes as the reduced number in the mouse. He has not counted 

 any spermatogonial complexes. His drawings show the chromo- 

 somes to be much better separated than is the case in the 

 majority of published mammalian studies. 



If we may judge the accuracy of the count from the character 

 of the published figures accompanying the above papers, I believe 

 that we are justified in accepting but few of the writers' conclu- 

 sions. The chromosomes are massed together, as shown in the 

 case of Wodsedalek's work on the pig, and it seems very likely 

 that fusion of the chromosomes has occurred in the various 

 forms mentioned above, as has been shown to have occurred 



