332 



developed cervical rib, over which the subclavian artery probably 

 passed. On the right the rib reached the sternum, its cartilage joined 

 that of the next rib, the two occupying the whole side of the manu- 

 brium. The lumbar, sacral and coccygeal regions are remarkably 

 normal. Kosenberg has apparently overlooked this case; for in his 

 second paper he alludes to a similar, but less complete case of 

 Gruber's and does not seem convinced that the observation is correct. 

 In the absence of measurements of the fresh spine the height of the 

 bodies of the vertebrae was measured and it appears that the 11 tho- 

 racic somewhat exceed the average length of 12. There is an unique 

 anomaly of the atlas consisting of the entire absence of the anterior 

 arch. The atlas is secured by a pair of strong ligaments passing 

 from either side of the odontoid to the lateral mass of the atlas: 



(Schluß folgt.) 



Nachdruck verboten. 



Longitudinal and TransTerse Dirisions of Chromosomes. 



By E. V. Wilcox, Ph. D. 



As is familiar to all students of cell anatomy and physiology, an 

 especial impetus was given to the investigation of the minute structure 

 and behavior of chromosomes by the theories of Weismann. Ever 

 since that time a great deal of attention has been devoted to a 

 detailed study of these cell organs, for the purpose of elucidating, so 

 far as possible, the mechanical processes of heredity. From extended 

 studies on reproductive cells instituted by Weismann and several of 

 his pupils, a scheme of chromatic divisions was formulated and pro- 

 mulgated as the one according to which the maturation divisions of 

 all animals would ultimately be found to take place. 



According to this scheme the chromosomes first undergo a longi- 

 tudinal division, followed immediately, without the intermediate con- 

 dition of the resting stage, by a transverse division. Great and far- 

 reaching significance was attached to each of these divisions and even 

 to the order in which they occur. The highly metaphysical inter- 

 pretations proposed by Weismann and his pupils are familiar to all 

 cytologists and need not be mentioned in this place. 



It is also a familiar fact that in studies on other animals by other 



