72 ME. E. J. HAEYET GIBSON ON THE STBTJCTTTEE 



"by an exceeding thin membrane through which pass very fine 

 strands of protoplasm. My friend Mr. Hick, of Owens College, 

 in his investigations on " Protoplasmic Continuity in the 

 Florideae "*, maintains that there exists " unbroken continuity of 

 the protoplasmic substances of the plant from the base of the 

 frond to the tips of the ultimate branchlets." 



"With a Zeiss T ^ oil-immersion lens I have been unable to con- 

 vince myself of the existence of the fine protoplasmic fibrillae 

 mentioned by Schmitz. I have seen what looked like extremely 

 fine threads passing between the " plugs " and the end of the 

 primordial utricle on either side ; but these seem to me to be 

 merely markings on the walls of the canals leading to the plugs. 

 I have examined the same phenomenon in the genus Polysi- 

 phonia t, where I have shown that such heterogeneous markings 

 do occur and give a deceptive appearance of interprotoplasmic 

 communication. In some genera undoubtedly protoplasmic con- 

 tinuity is maintained between all the cells of the frond during 

 life; but I cannot convince myself that that continuity, existing 

 as it certainly does in younger cells, is maintained in all old cells, 

 at least in the forms I have examined. 



Reproductive Organs. 



(a) Asexual. — The mother-cells of tetraspores are developed 

 from the cells of the inner rind of special ramuli. Each mother- 

 cell divides transversely by parallel walls, curved convexly out- 

 wards, into four daughter-cells ; and the mode of formation of 

 the tetraspores is therefore zonate. I have figured a young stage 

 and three adult sporangia. I have nothing further to add to 

 Kiitzing's description J. 



(b) Sexual Organs.— The antheridia and procarps are borne 

 on the same plant. Generally both male and female organs occur 

 close together on the same erect frond. A not infrequent condition 

 is that represented at fig. 11, PJ. XIV. I have occasionally found 

 the penultimate internode of an erect frond cystocarpic and the 

 ultimate internode antheridial. 



Antheridia.— The only account and figures of the antheridia 

 known to me are those of Buff ham in his paper already quoted. 

 The antheridial ramulus is, as Buffham says, easily distin- 



* Brit. Assoc. Keport, 1883, p. 547. 



t " Notes on Tolysiphonia fastigiata," Journ. Bot. xxix. no. 341 . 

 . t Tab. Plivc vol. xvi. tab. 71. 



