184 NOTES AND MEMORANDA. 



At maturity they are ejected with a jerk ; when free, they lie 

 for a while motionless enclosed in their gelatinous envelope 

 (a, h). Presently they assume a tremulous motion, at last 

 bursting the vesicle and swimming about. They are proto- 

 plasmic fusiform bodies of about 0"015 mill, in length ; 

 contents sparing, yellowish-red; at the anterior hyaline point 

 are borne two flagella, below which are two minute pulsat- 

 ing vacuoles (a, c). 



Shortly after their exit they are to be found in the neigh- 

 bourhood of the oogonia. The whole cavity of the oogonium 

 becomes pushed out laterally, dissolving and leaving an open- 

 ing at the apex of the expansion (b, c). The spermatozoids 

 seem now to be no way aimless in their movements, their 

 whole object being seemingly to effect a penetration ; with 

 great energy they drive against the wall, their anterior end 

 in advance — retreat — repeat the attack, and so persist for 

 hours. Still only those opposite the opening effect an entrance. 

 They swarm round the gonosphere or swim about in the in- 

 terior of the oogoniun in its free space (c). This lasts for five 

 or six hours or more, whereupon movement ceases, and they 

 shrink into formless little masses. The author, however, 

 was unable to directly perceive the actual confluence of the 

 spermatozoid with the gonosphere. But all must agree with 

 the author in his opinion that there can be no doubt but 

 that this agrees in nature and significance with similar ob- 

 served cases of fertilisation. 



The next change consists in the appearance of a thick 

 gelatinous stratum directly on the surface of the gonosphere, 

 which soon hardens into a doubly contoured membrane. 

 After some days the chlorophyll with the starch granules 

 gradually disappear, becoming replaced by the reddish- 

 yellow oily substance. In this way we obtain from the 

 gonosphere an oospore, surrounded by the mucous layers of 

 the oogonium [c,sp). The author could never see any further 

 development ; they lasted the whole autumn and winter with- 

 out the slightest alteration. 



It is curious that in some instances the gonosphores on 

 having become enclosed by the gelatinous envelope began 

 to germinate; they divided into two segments, each then 

 becoming clothed by its own gelatinous envelope, and soon 

 divisions followed just as in the ordinary vegetative joints (e). 

 The author supposes that these still green gonospheres could 

 not have been fertilised, and that only the latter pass over 

 into a state of rest. 



From the foregoing the author would place Cylindrocapsa 

 to the Ulothricheae, and suggests that Ulothrix itself may, 



