232 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 functionally 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 Gorystcs also takes place under certain conditions 

 in the allied form Atelecydus 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 antennae, 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, Alhunea 

 syrnnista, 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 antenna?. The antennal tube 

 has obviously been produced independently in Corystes and Alhunea, 

 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 Alhunea have yet 

 been made. 



It seems to me not unlikely that further observation of the habits of 

 Hippa tal'poida of the American coasts will reveal an essentially similar 

 sieve-like function for the curiously bent and setose second antenna? of 

 that animal. 



BIBLIOGRAPHY. 



Bell, T. [li'jZ).— British Stalk-Eyed Crustacea, pp. 159-163. 



Couch, J. (1878).— Cornish Fauna, 2nd Ed., pp. 75, 76. 



Dana, J. D. (1852). — "Cmstacea." U.S. Exploring Expedition, vol. xiii. 



Gossc, P. H. (1865).—^ 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). — " Braehyura." Challenger Reports, vol. xvii. 

 Milno-Edwards, II. (1834). — Histoire Nat. dcs Crustac^s, 3 vols. 



,, (1839.) "Reehcrches sur le Mecanisme de la Respiration ehez les Crustaces." 



^7171, Sci. Nat. (2) xi. pp. 129-142. 

 Robertson, David (1861). — "On the Uses of the Antenna? of Corystes cassivelaunus." 



Proc. Philosoi)h. Soc. Glasgow, v., completed 1864, jip. 55, 56 (with a good figure). 

 ,, (1886-88).— Proc. aiid Trans. Nat. Hist. Soc. Glasgoio, ii. {N.S.), pp. 143, 144. 

 Stabbing, T. R. R. (1893).— "A History of Crustacea." Int. Sd. Series. 



