80 NATURAL SCIENCE. JAN., 1893. 
THE WALK OF ARTHROPODS. 
I woucp like to supplement my paper on the ‘‘ Walk of Arthropods” (Nar. Sc1., 
vol. i., p. 676) by calling attention to Mr. Dixon's description of his researches, in 
Nature, vol. xlvii., p. 56, in which some additional details are given, not included in 
the paper reviewed by me. The spider (Tarentula) when running on water caused 
depressions of the surface-film which were projected as dark shadows on the bottom 
of the vessel. No shadows were cast by the foremost pair of legs, which proves that 
the spider, like the insects, has a triangular base of support. The walk of centipedes 
is also described ; the legs are said to move in alternate sets of three. 
In referring to investigators of the walk of insects, I regret that I omitted to 
refer to Professors Miall and Denny, who in their book on the cockroach (p. 79) 
give a short but excellent account of the locomotion of insects. 
Dublin, December, 1892. G. H. CARPENTER. 

DO CORRESPONDENTS. 
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OrFIcEs, 67-69 Chancery Lane, London, W.C. 
The PUBLISHERS require a few copies of the October number (no. 8) of 
Natura Science. Full price, with postage, will be paid for clean copies 
not folded, addressed to MACMILLAN & Co., 29 Bedford Street, Strand, London, 
W.C., until the demand 1s supplied. 
Proressor W. A. HerpMAN (University College, Liverpool) contemplates the 
preparation of a Handbook to the British Marine Fauna, and desires to receive 
suggestions from naturalists interested in the subject. He will also be glad to hear 
from specialists who are willing to co-operate with him in the compilation. The 
Professor proposes that the work should be a ‘“‘ pocket” or ‘‘ seaside’’ handbook, 
which could be used in much the same way as the botanists’ ‘‘ Field Flora.’’ It 
might comprise four to six small volumes, each dealing with one or two of the 
large groups. There would be definitions—perhaps with occasional analytical tables 
or keys—of orders, families, &c., down to and.including genera. Abbreviated 
descriptions of species would be added, with an indication of size, range, and 
habitat. Simple figures would be given of all structural features of diagnostic 
value in the various genera and species. 
