ON SOME NEWLY-FOUND ANTHEHIDIA. 339 



I have spoken more fully of the work of Harvey as there ap- 

 pears to have been little or nothing published in this country since 

 then on the microscopic features of the fruits of British marine 

 alga 1 , and any student desiring to add to our knowledge of this sec- 

 tion of our native flora should make the " Phycologia Britannica" 

 a starting point.* 



In the meantime continental botanists have worked assiduously 

 on the mode of reproduction of the Floridese. The most important 

 discovery was published by the French algologists Bornet et 

 Thuret who found an organ on several species which enabled them 

 to establish the true character of the three kinds of fruit named 

 above, and their discovery has given a renewed interest to this beau- 

 .tiful group. 



The tetraspores, then, are the asexual form of reproduction, and 

 are of the nature of gemma? or buds, and we thus clear the way 

 for a statement of the true sexual process. 



When a plant — say of Callitliamnion tetricum — is destined to 

 bear the true spores small rounded projections appear near the ex- 

 tremities of the ramuli, usually laterally, but in this species less so 

 than in most, and very early in its development, while still a pro- 

 carp, a minute process is put forth from near the apex of the 

 bulging part. This is the important organ the discovery of which 

 is above noted, and it is called the trichogyne. In Plate X., Fig. 

 1, I have drawn the mature unfertilised organ on a plant of C. tetri- 

 cum, as seen with i inch objective x 300. It consists of a hyaline 

 cylinder or tube expanding slightly into a bulbous apex, with a 

 slightly darker central axis which terminates at the base of the 

 bulb. At this stage I have not been able to detect certainly any 

 granulation. Measurements in these objects are of little value, for 

 the variability is great, but its length is about "002 inch, and its 

 diameter -0002. In Fig. 2 is a trichogyne of the same species X 

 500 (the procarp — not drawn — being in a similar stage of develop- 

 ment to the other). Attached to the trichogyne are three of the 

 minute ellipsoidal bodies from the antheridium called antherozoids. 

 These are also colourless, and their granular contents are in process 

 of transferring themselves through the hyaline exterior of the tri- 

 chogyne into its darker centre which now shows an irregular 

 granulation. Very shortly after this, in most species, the tricho- 



* I cannot sufficiently acknowledge my indebtedness to this invaluable 

 and unrivalled work. 



