354 J. G. WALLER ON PARASITIC VEGETABLE ORGANISMS. 



as have been described, though not in similar quantity. But it 

 serves to show us how interesting the question becomes, thus pur- 

 sued, when I tell you that this deposit has furnished two new forms 

 of singular interest. 



The first, I shall call your attention to, I must consider only as a 

 variety of the last described. Yet this does not diminish its value. 

 I pointed out that, that was remarkable mostly for its irregularity, 

 its contorted, ever varying Protean character, often an entangled 

 mass of filaments. Now, in the example under consideration, we 

 get something more definite ; the filaments are disposed in branch- 

 lets, and we find a close analogy thus with many of the Algje. 

 These branchlets are more superficial, and do not penetrate deeply 

 into the calcareous substance. Fig. 3, PI. XV., is taken from one 

 side of the particle, and shows the branch-like fronds distinctly. 

 Fig. 4 is on the other side, and although the filaments look de- 

 tached, it is not so, the stalk, as it were, being invisible from the 

 density of the medium and its descending deeper into the substance. 

 If we seek analogy to account for the larger globose object I have 

 spoken of, perhaps it may be seen in many of the Fungi. In Mucor 

 Mucedo, the branched mycelium, sending up a filament terminating 

 in a conidio- spore, appears to have something of the character, 

 although the form is different. All the other subordinate parts are 

 so completely like the last described, and the constant delicate 

 mycelium pervading the whole particle is so characteristic, that 

 I cannot but speak of this as a variation, though probably to 

 be considered as approaching a higher type of organization. 



Last, not least in interest, is a form peculiar, not hitherto found 

 at all. Viewing it alone, without any information as to its size, 

 &c, we might easily assume it to be a sponge. It is in a minute 

 particle of oyster shell, not exceeding the 20th of an inch, and the 

 longest diameter of the object is 100th of an inch. Were this a 

 sponge, we might rejoice in having the smallest in the world dis- 

 covered off our coasts. Everything at first sight favours the idea 

 of its being a minute Cliona. But we have to remember that, 

 hitherto, all these parasitic organisms have been referred to the 

 vegetable kingdom. Naturally, we should then look there for its 

 place, unless it was otherwise strongly marked. As we see it, it is 

 an excavating organism, which begins at one edge of the particle, 

 and sends out branches in different directions. This is not to be 

 accounted a peculiarity, but rather an accident, as other smaller 



