234 Kobert Wilhelm Ilegner. 



in the fat-body. They consisted of many transparent nucleated cells 

 which separated to form the testicular follicles or ovarian tubules, 

 about which a structureless membrane formed. 



In Tinea crinella, Balbiani (1869-72) found that "I'organe sexuel 

 est deja parfaiteraent perceptible a une epoque on Tembryon n'est 

 encore represente que par son rudiment ventral, et n'offre encore 

 aucune trace de ses autres appareils organiques. A cette phase pen 

 aA'ancee de son existence, I'organe reproducteur forme une petite 

 masse ovalaire simple, composee de minimes cellules rondes et 

 transparentes. . . Cette masse est appliquee a la face interne 

 de I'extremite inferieure du rudiment ventral. . . " This un- 

 paired oval mass later divided, one-half going to either side of the 

 body. 



Brandt (1878) did not study the early development of the germ- 

 cells but described both ovaries and testes in embryos of Pierls 

 hrassica just before hatching. ''Die Anlagen der Genitaldriisen 

 selbst fanden sich im Embryo an der Riickenwandung der Leibes- 

 h()hle, etwa im achten Korpersegmente, rechts und links dicht am 

 Ilerzen, dessen Peritonealliberzug auf sie iiberging. In ihrem jiing- 

 sten Entwicklungsstadium stellten si5 je eincn niehr oder weniger 

 elliptischen Korper dar, welcher durchweg aus rundlichen Embryo- 

 ludzellen mit amoboid gestalteten Kernen bestand." He found, as 

 did Ilerold (1815), that the female germ-gland could be distin- 

 gnislud from the male by its duct which extended from the posteri(n' 

 end, while in the latter the duct is attached to the side. 



O. and R. ITertwig (1881) found the rudiments of the germ- 

 glands of Zygcena minos lying between the somatic and splanchnic 

 layers of the mesoderm (Taf. II, Fig. 4). 



According to Graber (1891), both Tichomiroff (1882) and Sel- 

 vatico (1882) identified the germ-glands of Bomhyx inori in com- 

 paratively early embryonic stages. The earliest embryo examined 

 contained a germ-gland composed of a group of cells surrounded by 

 mesoderm. It lay between the "Proctodseum und dem Mescnteron" 

 in close connection "mit dem Faserblatt des Mitteldarmes." 



The male germ-glands of Zygcena filipendulco and other Lepidop- 

 tcra were found by Spichard (1886) to arise from the mesoderm and 



