Makch 7, 1913] 



SCIENCE 



383 



bility that Klebahn saw stages in a single form 

 and not two distinct varieties. I have been unable 

 to find a fusion of many nuclei in the egg as 

 described by Golenkin, nor a multinucleated egg 

 as described by Klebahn. 



All nuclear divisions are mitotic, not simply the 

 earlier divisions as noted by Golenkin. There is 

 no fragmentation of the nucleolus to form the 

 chromosomes. 



Fertilization does not take place until the egg 

 is fully formed and rounded up ; at this time the 

 egg nucleus lies in the center of the egg. 



The pyrenoids vary greatly as to size and shape, 

 and the starch is often found to be very irregularly 

 arranged around the central structure. 



A Comparison of Plant and Animal Spermato- 

 genesis: Charles E. Allen, University of 

 Wisconsin. 



The development of the androcyte of Poly- 

 trichum juniperiimm into the antherozoid is in 

 several respects closely parallel to the correspond- 

 ing metamorphosis of the spermatid in certain 

 animals, notably in mammals. For present pur- 

 poses comparison will be made with the sperma- 

 togenesis of the guinea-pig, well known through 

 the researches of Meves. 



1. In both spermatid and androcyte the nucleus 

 is at first central, then comes to lie at the extreme 

 side or end of the cell. It undergoes a great 

 diminution in volume, its contents becoming denser 

 and finally homogeneous. The nucleus of the 

 spermatid is finally fiattened and curved into the 

 form of the bowl of a spoon ; that of the androcyte 

 is drawn out into a long spiral filament. 



2. The spermatid possesses two central iodies; 

 the androcyte contains the blepharoplast, whose 

 ceutrosomic nature is a disputed question. From 

 one of the central bodies a contractile filament 

 grows out which becomes the axial filament of the 

 vibratory tail. From the blepharoplast grow out 

 two cilia. Out of the central bodies is developed 

 the end hnoh or middle piece of the spermatozoon; 

 the blepharoplast forms the anterior end of the 

 antherozoid; in each case the part of the male 

 cell in question is that to which the motile appa- 

 ratus is attached. 



3. The sphere or idiosome of the spermatid 

 divides into two portions; one, the acrosome, forms 

 the anterior end of the spermatozoon; the other, 

 a spherical mass, passes to the posterior part of 

 the cell and is finally discarded with other unused 

 portions of the cytoplasm. The young androcyte 

 contains a spherical body which, like the idiozome. 



divides into two; one lies close to the anterior end 

 of the blepharoplast, and perhaps persists in the 

 mature antherozoid as a delicate sheath about the 

 blepharoplast; the other, which has been called by 

 Ikeno (incorrectly) the chromatoid Nebenkorper 

 and by M. Wilson the limosphere, places itself in 

 contact with the posterior end of the elongating 

 nucleus and is discarded with the remaining cyto- 

 plasm after the antherozoid becomes free. 



4. The androcyte contains a small spherical body 

 which seems to persist but a short time and has no 

 discoverable function; it may be compared with 

 the chromatoid Nebenkorper or with the Neben- 

 kern of the spermatid, both of which are con- 

 spicuous, but temporary and apparently func- 

 tionless. 



5. That part of the cytoplasm in both spermatid 

 and androcyte which is not used in forming the 

 mature cell rounds up 'into a vesicle; this cyto- 

 plasmic residue is discarded by the spermatozoon 

 before maturity, and by the antherozoid after its 

 escape from the antherid. 



How far the similarities noted are due to a 

 series of homologies, and how far to the fact that 

 a similar problem is to be worked out by two cells 

 similar but of widely divergent origin, must be 

 left for the present an open question. 

 Intermingling of Perennial Sporophytic and 



Gametophytic Generaiions in Busts: E. W. 



Olive, Brooklyn Botanic Garden. 

 The Individuality of Chromosomes in the Somatic 



Cells of Gentiana procera: R. H. Denniston, 



University of Wisconsin. 



The nuclei in the cells of the nucellus and in- 

 tegument were the ones especially studied. 



The material is favorable, because the chro- 

 matin appears in the resting stages in deeply 

 stained, well-defined masses. 



In this plant there is a large number of chro- 

 mosomes, about eighty. These appear closely 

 massed together in the equatorial plate stage. 



In the metaphase the chromosomes are pulled 

 away from each other toward their respective 

 poles. In this view the chromosomes appear as 

 short curved rods. 



The chromosomes do not lose their identity in 

 the diaster stage, as here and there an individual 

 can be plainly seen projecting from the mass. 



The long axes of the individual chromosomes 

 conform in general direction with the long axis of 

 the spindle. 



After the closely packed condition of the chro- 

 mosomes in the diaster, they move apart somewhat, 



