72 G. M. Giles — On the Protliallus o/Padina pavoiiia, [No. 2, 



Some days ago, while collecting marine algee amongst the rocks of 

 Kjouk Phyou harbour, a place was visited where this plant was excep- 

 tionally abundant. It was also as remarkable for its bareness of other 

 algee, the only others present being Caiderpa sedoides and a small rhodos- 

 perm not in fruit but probably belonging to the genus Acantliopliora, and 

 even these were very few and far between. 



On the rocks on which the Padina were growing was noticed a 

 number of small bodies about 5 mm. in diameter of a beautiful deep green 

 colour, and generally of oval outline. Some of these were growing 

 actually on the fronds of the Padina, while immense numbers were 

 clustered on the rocks around. 



On closer examination, with a pocket lens, it was seen that in many 

 instances very young fronds of the Padina were sprouting from the 

 circumference of the green bodies- On taking these up, it was observable 

 that the little buttons of tissue were beginning to shrivel and decay, and 

 that the young Padina fronds were firmly attached to their remains. 



These circumstances appeared to point to some intimate connection 

 between the two growths, and a number of the " prothalli " were 

 accordingly collected and carried back to the ship for more minute 

 examination. 



On placing one of them beneath a Coddington lens, it was seen that 

 the green substance was encased in a coating of white transparent tissue, 

 much thicker and more opaque on its under than on its upper surface. 

 The green substance itself was beautifully marbled with oval or circular 

 markings of a deeper green than the rest. 



These points having been noted and drawn, one of the specimens 

 was placed in the microtome and a number of transverse sections taken. 

 On placing these beneath the microscope, a structure of really wonderful 

 complexity was dis2Dlayed (Fig. 3.) Enveloping the mass is the white 

 tissue, in which, so far as could be seen, there are no apertures. This 

 tissue is composed of a network of stellate cells with anastomosing tails, 

 exactly like the structure known in animal histology as adenoid con- 

 nective tissue ; in the meshes of this, on the under surface of the 

 prothallus, are enclosed a number of opaque bodies to be more minutely 

 described further on. Enclosed in this are a number of tubular bodies, 

 containing the reproductive organs, supported by bands of tissue spring- 

 ing from the peripheral layer. The space between these is filled up by 

 a mass of spherical nutritive cells containing abundant chlorophyll. 



To return to the " tubular " bodies. These are scattered, in masses, 

 irregularly through the central substance ; and, on closer examination, 

 there are readily distinguishable in each mass two kinds of bodies, 

 differing markedly in size and contents, though evidently primarily of 

 the same morphological character. 



