260 MONTGOMERY A STUDY OF THE CHROMOSOMES 



1899b. Cytological Studies, with especial Regard to the Morphology of the Nucleolus. Journ. Morph. 15. 



1901. The Spermatogensis of Peripatus (Peripatopsis) balfouri up to the Formation of the Spermatid. Zool. 



Jahrb. 

 1895. MOORE, J. E. S. : On the Structural Changes in the Reproductive Cells during the Spermatogenesis of Elas- 



mobranchs. Quart. Journ. micr. Sci. (N. S.) 38. 



1872. OELLACHER, J. : Beitriige zur Qeschichte des Keimblaschens im Wirbelthiereie. Arch. mikr. Anat. 8. 

 1898. PAULMIER, F. C. : Chromatin Reduction in the Hemiptera. Anat. Anz. 14. 



1899. The Sperraatogenesis of Anasa tristis. Journ. Morph. 15, supplement. 



1885. RABL : Ueber Zelltheilung. Morph. Jahrb. 10. 



1855. REMAK : Untersuchungen iiber die Entwicklung der Wirbclthiere. Berlin. 



1894. RUCKEBT : Zur Eireifung bei Copepoden. Anat. Hefte, IV, 2. 



1895. TJeber das Selbstaudigblciben der vaterlichen und mutterlichen Kernsubstanz wiihrend der ereten Ent- 

 wicklung des befruchteten Cyclops-Eies. Arch. mikr. Anat. 45. 



1897. SABASCHNIKOFF, M. : Beitrage zur Kenntniss der Chromatin reduction in der Ovogenese vom Ascaris mega- 

 locepbala bivalens. Bull. Soc. impe'r. Nat. Moscow. 



1887. SCHULTZE, O. : Ueber die Karyokinese in den crsten Zellen des Axolotl. Sitzber. phys. rned. Ges. Wiirzburg. 



1888. SCHWABZ, E. : Ueber embryonale Zelltheilung. Mittheil. embryol. Inst. Wien. 



1897. SOBOTTA : Die Reifung und Befruchtung des Eies vom Amphioxus lanceolatus. Arch. mikr. Anat. 50. 



1888. TOBOK, L. : Die Theilung der rothen Blntzellen bei Amphibien. Ibid., 32. 



1875. TBINCHESE : I priini moment! dell' evoluzione nei Molluschi. Atti R. Accad. Lincei. 



1883. VAN BENEDEN, E. : Recherehes sur la maturation de I'oeuf, la fecondation et la division cellulaire. Gand. 



1887. VAN BENEDEN and NEYT : Nouvelles recherches, etc. Bull. Acad. Roy. Belg. 14. 



1892. VON RATH, O. : Zur Kenutniss der Spermatogenese vom Gryllolalpa vulgaris Latr. Arch. mikr. Anat. 40. 



1893. Beitrage zur Kenntniss der Spermatogenese vom Salamandra maculosa. Zeit. wiss. Zool. 57. 



1900. WALLACE, LOUISE : The Accessory Chromosome in the Spider. Anat. Anz. 18. 



1897. WHEELEB, W. M. : The Maturation, Fecundation and early Cleavage of Myzostoma glabrum Leuckart. 



Arch, de Biol. 15. 



1890. ZIMMERMANN, K. W. : Ueber die Theilung der Pigmentzellen, etc. Arch. mikr. Anat. 36. 



EXPLANATION OF THE PLATES. 



All figures have been drawn with the camera lucida at the level of the base of the microscope, with the homo- 

 geneous immersion objective -f t of Zeiss and ocular 4, tube length 180 mm. In the majority only the Chromatin 

 nucleoli, chromosomes and true nucleoli together with the outline of the nucleus or cell body has been drawn ; and 

 in the majority of figures representing lateral views of monaster stages, the mantle fibres, connective fibres, and 

 centrosomes are the only structures shown beside the chromatin elements. For Eucliistui variolariits, however, the 

 various structures are represented in detail, and this is also the case with some of the figures of various other species. 



The following abbreviations have been employed (for others not here mentioned the descriptive text must be 



referred to): 



C. Mb., cell membrane. 



N., true nucleolus (plasmosome). 



N. S, chromatin nucleolus (modified chromosome). 



N. Mb., nuclear membrane. 



Plate 1. 



Euchittus variolariug, Figs. 1-19 



Fig. 1. Nucleus of spermatogonium, rest stage. 

 Figs. 2, 3. Pole views of spermatogonic monasters. 



