2a2 CONTRIBUTIONS TO MARINE BIONOMICS. 
The upright position of the crab is itself a most unusual feature, and 
is correlated with the formation of an elongated antennal tube; the 
posterior position of the legs is WIL BaEy correlated with the adoption 
of the upright attitude. 
VI. ANALOGIES. 
A reversal of the respiratory current similar to that which I have 
just described in Corystes also takes place under certain conditions 
in the allied form Afelecyclus heterodon. The habits of this crab are 
much more complex than those of Corystes, and will form the subject of 
a later article. 
An elongation of the antennz, and their conversion into an antennal 
tube by the interlocking of hairs along their margins, also takes place, 
as I have recently discovered, in an East Indian Crustacean, Albunea 
symnista, Fabr., which belongs to the Hippinea among the Macrura 
Anomala (Anomura). In this type, however, the antennal tube is formed 
by the first and not by the second pair of antenne. The antennal tube 
has obviously been produced independently in Corystes and <Albunea, 
and affords a remarkable example of homoplastic modification. In 
all probability the function of the tube is the same in both cases, but 
no direct observations on this head in the case of Albunea have yet 
been made. 
It seems to me not unlikely that further observation of the habits of 
Hippa talpoida of the American coasts will reveal an essentially similar 
sieve-like function for the curiously bent and setose second antennz of 
that animal. 
BIBLIOGRAPHY. 
Bell, T. (1853).—British Stalk-Eyed Crustacea, pp. 159-163. 
Couch, J. (1878).—Cornish Fauna, 2nd Ed., pp. 75, 76. 
Dana, J. D. (1852).—‘‘Crustacea.”” U.S. Exploring Expedition, vol. xiii. 
Gosse, P. H. (1865).—A Year at the Shore, pp. 127-131. 
Haan, W. de (1850).—‘‘ Crustacea.” Siebold’s Fauna Japonica. 
Hunt, A. R. (1885).—‘‘On the Influence of Wave-Currents on the Fauna inhabiting 
Shallow Seas.” Proc. Linn. Soc., xviii. Zool., p. 269. 
Miers, E. J. (1886).—-*‘ Brachyura.” Challenger Reports, vol. xvii. 
Milne-Edwards, H. (1834).—Histoire Nat. des Crustacés, 3 vols. 
5, (1839.) ‘‘Recherches sur le Mécanisme de la Respiration chez les Crustacés.” 
Ann. Sci. Nat. (2) xi. pp. 129-142. 
Robertson, David (1861).—“On the Uses of the Antenne of Corystes cassivelaunus.” 
Proc. Philosoph. Soc. Glasgow, v., completed 1864, pp. 55, 56 (with a good figure). 
5, (1886-88).—Proc. and Trans. Nat. Hist. Soc. Glasgow, ii. (N.S.), pp. 143, 144. 
Stebbing, T. R. R. (1893).—‘‘ A History of Crustacea.” Int. Sci. Series. 
