582 



CELL DIVISION IN EGGS OF CREPIDULA. 



Wasielewski, W 



1902, 1903. 



wiss. Bot., XXXVIII, XXXIX 



Experimentelle Beitrage zur Kenntnis 



Jahrb 



Wilson, E. B 



1894. 



Mosaic 



Woods 



1896*. The Cell in Development and Inheritance. New York. 



1897. 



Middle Piece in the Fertilization 



Science, V. 



1900. The Cell, etc. 2d Ed. Id. 



1901. Experimental Studies in Cytology 

 1901. Experimental Studies in Cytology 



Mech.. XII 



XIII 



1904 



Germinal Localization. Journ. Exp 



ZlEGI 



H. E. und v. Rath, O 



1891. 



amitotische Kernteilung bei den Arthropoden. Biol. Centralb., XI. 



ZlEGI 



H. E 



1891. 



Bedeutung der amitotischen Kernteilung 



18951 Untersuchungen liber die Zellteilung. Verh. .deutsch. ZooL Ges. 

 1898. Experimentelle Studien iiber die Zellteilung 



Id., XI. 



Mech 



1903. Experimentelle Studien iiber die Zellteilung 



Biol. Centralbl., XVI. 



XIV. EXPLANATION OF PLATES XLIII-LIX. 



All figures represent whole eggs of Crepidula plana, fixed,- stained and mounted in balsam. They 

 drawl at stage level, with camera lucida, under Zeiss' Apochromatic Horn Immersion Objecuve 3 

 or lification of 333 diameters. In the process of reproduc- 



The polar bodies are in all cases shaded by parallel lines, 



mm., Comp. Ocular 4, and represent a mag 



tion they have been reduced about one-fifth. 



while the crenated fine which appears in most of the ngu 



line of yolk spherules surrounding the cytoplasmic area. 1 



outline, as are also the cells and nuclei which lie at lowei 



thoueh normal eggs are found in many of the experiments. 



shown 



abnormal 



Reference Letters. 





A, B, C, D 



la-Id 



2a-2d 



3a-3d 



4d 



Am. 



As. 



Ch. 



Ch.V. 



End. 



F.C. 



G.V. 



L. 



M. 



Memb. 



N. 

 Nl. 

 9N 



Pb 

 PCp 



SkG. 



S.G. 



Sp. 



V. 



Y. 



Z. 



Macromeres. 



1st set of micromeres 



2d set of micromeres. 



3d set of micromeres. 



Mesentomere. 



Amphi aster* 



Cyt aster. 



Chromatin, 



Chromosomal vesicle 



Endoderm. 

 Follicle cells. 



Germinal vesicle. 



Lobe. 



Mesomere. 



Cell membrane. 



Nucleus. 



Nucleolus. 



Egg nucleus. 



Sperm nucleus. 



Polar bodies. 



Posterior cell plate. 



Sphere. 



Shell gland 



granules 



Spindle. 

 Velum. 

 Yolk. 

 Zwischenkorper 



