08 MEMORANDA. 



those next to it. These rings are articulated by some inter- 

 vening dark matter laid transversely. 



The tube thus formed is occupied by a series of clear 

 vesicles of the same length as the siphons, which im]:)ress 

 upon their outer surfaces a set of corresponding parallel 

 depressions, and each vesicle contains an urn-shaped body of 

 the same colour as the siphons. A row of spines is placed 

 round the shoulder of this organ, and from either end a stem 

 with a slightly-expanded termination passes out, by which all 



the vesicles and their contents are 

 brought into connection. These 

 urn-shaped bodies when immedi- 

 ately below a bifurcation of the 

 frond are rather more squared 

 than the rest, and give out a com- 

 municating process from each of 

 the distal angles. The chain is 

 in this manner continued upwards. 

 The contents in the conditions in 

 which I have seen them are mere 

 granular matter. The same or 

 corresponding structures have not 

 been observed in other species of 

 Polysiphonia ; but in the frond 

 of P. fastigiata, producing tetra- 

 spores, they are present. 



No description or representa- 

 tion of them has yet been pub- 

 lished, and their functional rela- 

 tions remain unknown. 



Polysiphonia. 



A. Terminal portion of a frond of Polysiphonia fastigiata, bearing 



antheridia. 



B. Transparent cells containing urn-shaped bodies from interior of 



frond. 



C. Urn-shaped body in cell from a part of the frond immediately 



below a bifurcation. 



Further remarks on the Fly's Foot. — If Mr. Tyrrell's theory be 



correct, " That the Fly uses the hooks as levers to detach the 

 foot," we should expect a jyriori that the Beetle did so : but 

 the contrary is the fact. I placed one (not aquatic, or of the 

 Curculio tribe) under the microscope, feet upwards, which 

 was remarkably slow in its movements, and furnished with 

 two circular pads, and one triangular, possessing trumpet- 

 shaped hairs, and having the power of secreting fluid. When 

 detaching the foot in walking, it raised the hooks first, and 



