Journal of Applied Microscopy. 399 



drawn out into poles at opposite sides of the nucleus. The spindle fibers of 

 either pole may be of unequal length, but all converge toward a common point. 

 Some of the figures suggest that other interpreters might claim for them the con- 

 dition of multipolarity. The nuclear membrane does not often disappear until 

 the achromatic spindle is almost formed, and there is no evidence justifying the 

 statement that it contributes to the formation of the spindle. The form of the 

 spindle is determined by the dimensions of the dividing cell. The development 

 of the spindle in cells of the plerome shows characteristic differences from the 

 same process in cells of the periblem. 



At about the time the nuclear membrane disappears the chromatin thread 

 breaks up into a few divisions, and these break again, forming the chromosomes. 

 If the chromosomes are short they are placed parallel to the spindle threads, 

 while if they are long there is no regularity in their position. Some spindle 

 fibers pass directly from pole to pole, while others are attached to the chromo- 

 somes. The chromosomes split longitudinally, beginning at the looped end. 

 After the pairs of chromosomes have divided somewhat, fibers are seen connect- 

 ing them, and Nemec states that these fibers are entirely different in structure 

 from those which first formed the spindle. They are thicker, more granular, and 

 stain more like chromatin than the earlier formed fibers. As to their function, 

 he says any statement would at present be a mere guess, but suggests that they 

 may, by exerting a push, assist the fibers which are pulling the chromosomes. 



Structures which have been described by some other writers as centrosomes 

 are represented in the drawings, but the author thinks they are nucleoli, since 

 they react toward stains as nucleoli, and are finally enclosed within the nuclear 

 membrane. 



The statement is made that the chief morphological difference between the 

 division of cells of vegetative tissue, and those of sporogenous tissue, consists in 

 the fact that the spindle in divisions of the former is always bipolar, while that 

 of the latter may be multipolar at the beginning, and may or may not become 

 bipolar. 



Throughout the paper few references are made to work done by others along 

 these same lines ; and while the work is very similar, and in some cases a repeti- 

 tion of that done by Schaffner on Allium Cepa, and published by him in the latter 

 part of last year, no reference is made to this work. 



Otis W. Caldwell. 

 Chicago. 



Goldfius, Mile. Mathilde. Sur la structure et les The author has made an extensive study 



fonctions de I'assise epitheliale et des ami- ^f ^^^ embryo-sac and surrounding 



podes chez les Composees. Journ. de . -^ ° 



Botanique, 12: 374-384, 1898: 13: 9-17, tissues in composite ovules, from a point 



49-59. 87-96. 6 pis., 1899. of yig^ ^l^i^j^^ ^I^-jg ^Q^ ^g^^ jg unusual. 



It is well known to all students of composite ovules that the embryo-sac, 

 before maturity, ruptures the nucellus, and, continuing its growth, pushes the 

 heavy integument away from the funiculus, forming for itself a spindle-shaped 

 cavity. This cavity is, of course, lined by the epidermis, and the cells border- 

 ing upon the sac, having a perfectly columnar form, were called etidodermis by 

 Hegelmaier, and endothelium by Schwere. Mile. Goldflus has suggested the term 



