ON SArROLEGNI^E. 119 



tubos, similar to those which form tlie zoosporangia, ond represent 

 so many distinct little masses of plasma in the midst of a homo- 

 geneous and parietal ganglium ; the contents of these plastic masses 

 are soon delineated in a more precise manner ; we sec in their in- 

 terior some homogeneous grannies, which are at first globose, then 

 oval, and finally pass to the enlarged and ampulla; form extremity 

 of the generating tube ; there they become rounded or oval cells, 

 covered with cellulose, and emit from their surface one or several 

 cylindrical processes, which elongate towards the wall of the con- 

 ceptacle, and pierce it, without, however, ever projecting very far 

 beyond it. At the same time the lacunose plasma of each cell is 

 divided into a multitude of corpuscles, the diameter of which equals 

 about '004 m.m. ; these escape by the open extremity of the cylin- 

 drical neck of which we have spoken, and, as regards their 

 organization and agility, they resemble the spermatozoids of Aclilya 

 dioica. In water these corpuscles quickly become motionless, and 

 do not germinate. During the development of these organs, the 

 protoplasm of the utricle, which contains them, offers at first quite 

 normal characteristics, and disappears entirely by degrees as they 

 increase. That these organs belong really to the Saprolegnia, 

 which presents them and constitute its antheridia, there are good 

 reasons to believe, as M. Pringshcim has shown. Another opinion, 

 which the same author refutes, is that the corpuscles in question 

 are parasites from outside, entered into the cavities of the Sapro- 

 legnia, and which fructify at the expense of its protoplasm. This 

 opinion relies principally on the great resemblance of these 

 corpuscles to certain veritable parasites, such as Chytridium. It 

 may also be supported by the fact that M. Pringsheim has some- 

 times observed near the corpuscles in question, and in their con- 

 ceptacles, globules similar to those which have been often met with 

 in the Sjnrogyrce, the Vaucherice, and other Algre, and which belong 

 incontestably to vegetables which are parasitic upon them. The 

 reasons which M. Pringsheim brings against this appreciation 

 ought to have lost some of their value in consequence of the new 

 observations which have been made on the biology of microscopic 

 parasites, and the whole subject should be studied again. More 

 ample details concerning the sexual organs of the Saprolegnia] will 

 be found in the already quoted works of this celebrated Algalogist. 



The oospores of the Saprolegnice, when they have arrived at their 

 maturity, possess, like many other spores, a tolerably thick integu- 

 ment, which is double, viz., formed of an epispore and an endospore. 

 After a considerable time of repose, they originate tubular or 

 vesicular germs, and, by exception, these germs are only as yet 

 slightly elongated, when they produce zoospores. 



Hitherto it has not been possible to obtain a direct experimental 

 proof of the reality of a fecundation in the Saprolegnia?, unless 

 we can consider as such an instance observed by M. Pringsheim, 

 in which the multitude of the gonospheres of a Saprolegnia perished 



