A Monograph of the Gemis Alaria. 33 



embryonal frond of Homœostroma will illustrate the evolution of 

 Encœliacea3 from a more primitive form such as Striariaceas. 



As for the cryptostoma of Fucaceœ, it may be explained to 

 be a sterile conceptacle according to Bowek^) and Simons 2). Or, 

 according to Oltmanns' ^) view, the conceptacle may be a fructified 

 cryptostoma. But Barton's*) view that " the two forms of con- 

 ceptacles are of equal antiquity, and were a later development in 

 the ancestors of the Fucaceaß than the reproductive organs," may 

 be open to criticism. We know very little, if anything, about the 

 ancestors of Fucacea3. If, however, ontogeny repeats phylogeny, 

 the tuft of hairs in the apical pit of the sporelings of Fucus sug- 

 gests to us to prefer the view that the cryptostoma is an important 

 vegetative organ of the Fucaceous frond and that its development 

 is earlier than that of the conceptacle. 



Murray^) says : — " I am aware that the hairs of the crypto- 

 stomata are regarded by many as adapted to absorptive and other 

 nutritive functions. This may or may not be ; there is no proof 

 of the matter, and probably more reasons to be cited against than 

 in favour of, such an opinion." He has not treated the matter 

 further and we are not able to know what was his opinion re- 

 garding the functions of the hair-tufts of Alaria. The view held 

 by some botanists, that the hairs of the Phaeophyceœ are a pro- 

 tecting organ against the light is undoubtedly derived from the 

 accounts of the hairs of the Phanerogams. This can be readily 

 denied when we consider the fact that the blades of the Phœophy- 

 cea3 which are habitually decumbent have the hairs developed on 



1) Bower : On the Development of Conceptacles in the Fucacete, p. 37. 



2) Simons : Morphol. Study of Surg, filipendula, p. 174. 



3} Oi.TM.4NNs : Beitrage znr Kenntnis der Fucaceen, p. 82. 



4) Bakton : On the Geniis Turbinarla, p. 223. 



5) MrEBAY: Phyc. Memoirs, X, p. 63. 



