24 COCCOPHYCEJ3. 



a protoplasmic gonosphere, coloured by chlorophyll, containing numerous 

 starch granules ; it presents at one point of the periphery very often a 

 clear spot. The gonosphere is loosely enclosed by the several (3-6) con- 

 centric gelatinous (as it were swollen or expanded) membranes. Such 

 oogonia lie either several together, forming a moniliform chain, or they 

 present themselves in the middle of a series of antheridia, or betweeu 

 unaltered vegetative joints, upon which, further on, may abut antheridia. 

 Cylindrocapsa is thus monoicons. At both poles of the oogoninm the 

 coats are produced into a short cylindrical process ; adjoining processes 

 are mutually apposed. The size of the oogonia varies ; it may reach 

 042 mm., the gonosphere '024 mm. 



" The antheridia are discoid or sphseroidal little cells, like the oogonia 

 possessing a multi-laminated coat, they may form a long series or little 

 groups of pairs ; they are often enveloped in twos or fours by numerous 

 laminae. The contents are clear reddish yellow. The male cells (like 

 the vegetative) are formed by binary division of the mother joint, with 

 the distinction that they cease to grow, remain smaller, and gradually 

 assume the yellowish red colour. Each antheridium developes by divi- 

 sion of its contents two spermatozoids. At maturity they are ejected 

 with a jerk ; when free, they lie for a while motionless enclosed in their 

 gelatinous envelope. Presently they assume a tremulous motion, at last 

 bursting the vesicle and swimming about. They are protoplasmic fusi- 

 form bodies of about '015 mm. in length, contents sparing, yellowish 

 red ; at the anterior hyaline point are borne two flagella, below which 

 are two minute pulsating vacuoles. 



" Shortly after their exit they are to be found in the neighbourhood 

 of the oogonia. The whole cavity of the oogonium becomes pushed out 

 laterally, dissolving and leaving an opening at the apex of the expansion. 

 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, and retreat, and so persist for hours, 

 until at last the movement ceases, and they shrink into formless little 

 masses. The actual confluence of the spermatozoid with the gonosphere 

 was not observed, but the conclusion drawn by the author seems to be 

 legitimate. 



" 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. The 

 author could never see any further development ; they lasted the whole 

 autumn and winter without the slightest alteration. 



" In some instances the gouospheres 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. 

 The author supposes that these still green gonospheres could not have 

 been fertilized, and that only the latter pass over into a state of rest." 

 Quart. Journ. AJicr. Sci., 1877, p. 181. 



GENUS 17. HYDRURUS. Ag. (1824.) 



Thallus adnate, gelatinous, more or less firm, tubular, elon- 

 gated (2-4-12 inches long), sometimes variously divided, sticky, 

 surface naked or densely covered with delicate fibres, which at 

 times are fasciculate. Cells in the beginning globose, or sub- 



