198 



seems to suppose, continuous masses of chromatic substance but each 

 one consists of two distinct chromosomes connected by linin threads, 

 and should therefore be designated hj ab or any other two letters, 

 and not, as Wilson's formula would require, by a a or bh. 



We have abundant reason to believe from the divergent published 

 accounts of the two maturation divisions that the processes are not 

 so remarkably uniform in all animals as to admit only one formula for 

 all. It is quite probable that the observed and recorded instances 

 are but the various manifestations of a more fundamental law which 

 is as yet not even formulated. The progress of biology has exhibited 

 a frequent mistaking of special instances for the general law, and 

 that may be the case in this particular field. 



Believing that he had discovered inherent inconsistencies in my 

 published account, Wilson apparently did not deem it necessary to 

 ofier any real criticism of my position. But since I have shown that 

 Wilson's remarks are based on an erroneous interpretation, the case 

 simply stands as it was. 



Bozeman, Mont., Oct. 29, 1897. 



Literati! re cited. 

 '92 Wagnek, J., A Review of the present Condition of the Question 



as to the Existence and Meaning of Fertilization. (Russian.) Rev. 



des sei. nat., St. Petersbourg. 

 '95 Wilcox, E. V., Spermatogenesis of Caloptenus femur-rubrum and 



Cicada tibicen. Bull. Mus. Comp. Zoöl. Harvard College, Vol. XXVII, 



No. 1, p. 1-32, PI. I— V. 

 '96 Wilson, E. B., The Cell in Development and Inheritance. New 



York, The Macmillan Co. 

 '97 GoDLEwsKi, E. jun., Ueber mehrfache bipolare Mitose bei der Sper- 

 matogenese von Helix pomatia L. Anz. der Akad. der Wiss. in 



Krakau, p. 68 — 81. 



Nachdruck verboten. 



Variation homoeotique unilaterale chez Toryet. 



Par A. Cligny^ Agrege-preparateur de Zoologie ä l'Ecole Normale 

 Superieure — Paris. 



Avec une figure. 



Le nombre des vertebres est assez variable chez les reptiles dans 

 r^tendue d'une meme espece, particulierement pour les ophidiens et 

 les sauriens rampants. Si Ton Studie une region sp6cialis6e et bien 

 d61imit6e de la colonne vert6brale la variation peut survenir selon 



