FEMALE REPRODUCTIVE CELLS 477 



the yolk is usually softened and may be cut. Or, by fixing the ova of 

 Loligo in osmicacid until the outer blastoderm is killed, and then remov- 

 ing to a very dilute solution of chromic acid, the yolk may be completely 

 dissolved. 



In refractory cases, celloidin combined with paraffin is used, and for 

 some ova celloidin alone, which makes it hard to cut thin enough sections 

 or to secure a good series. Many studies have been performed by smear 

 preparations with the same limitations as have been mentioned in the 

 case of the male reproductive cells. A very important method is to 

 study some ova in the living state or to slice or tease off the blastoderm 

 and mount it whole. 



LITERATURE 



BOVERI, T. "Zellen Studien." Jena, 1887. 



KIRKHAM, W. B. "Maturation of the Egg of the White Mouse," Trans, of Conn. Acad. 



of Arts and Sci., Vol. XIII, 1907. 

 PHILIPS, E. F. "A Review of Parthenogenesis," Proc. Am. Phil. Soc., Vol. XLII, p. 174, 



1903. 

 STEVENS, N. M. "A Study of the Germ Cells of Aphis rosce. and Aphis cenothera," 



Journ. of Exp. Zool., Vol. II, 1905, p. 313. 

 BRAUER, A. "Zur Kentniss der Reifung des parthenogenetisch sich entwickelnden Eies 



von Artemia salina," Arch.f. mik. Anat., Band XLIII, 1893. 

 LAMS et DOORME, "Nouvelles Recherches sur la Maturation et la Fecondation de 



Poeuf des Mammiferes," Arch, de Biol., T. XXIII, 1907. 

 CONKLIN, E. G. " Karyokinesis and Cytokinesis in the Maturation, Fertilization, and 



Cleavage of Crepidula," Journ. Acad. Nat. Sci., Phila. '2, i, 1902. 

 MUNSON, J. R. "Researches on the Oogenesis of the Tortoise, Clemmys marmorata," 



Am. Journ. Anat., Vol. Ill, p. 311. 

 GOLDSCHMIDT, R. " Untersuchungen liber die Eireifung, Befruchtung, und Zellteilung 



bei Polystomum integrimum Rud.," Zeit. Wiss. Zool., Band LXXI, S. 379, 1902. 

 JORDAN, H. E. "On the Relation between Nucleolus and Chromosomes in the Maturing 



Oocyte of Asterias forbesii," Pub. Carnegie Inst. of Wash. Pub. No. 102, 1908. 



