LARVAE OF DECAPOD CRUSTACEA 399 



(4) In Amphion leg 5 is reduced and unbranched. In some specimens the leg is 

 absent, and this may be a sexual difference as Zimmer claims it to be in Amphionides. 



(5) In specimens oi Amphion which lack leg 5 pleopod i is uniramous and rather long. 

 This may also be a sexual difference foreshadowing the difference found in Amphionides. 

 On the other hand Zimmer states that pleopod i is uniramous in both sexes of 

 Amphionides, and it becomes necessary to assume that the rudimentary endopod found 

 in female Amphion disappears later. 



(6) According to Zimmer the digestive system is the same in both forms, and there is 

 much similarity in the nervous system also, so far as it can be seen. 



It is not claimed that this evidence amounts to any more than a justification for putting 

 forward the proposition that Amphion and Amphionides may be one genus; but it is, 

 at least, a possibility and, in my opinion, a probability. The fact that Amphion may be 

 taken at Bermuda and kept alive for a considerable time raises the hope that the solution 

 of this problem by direct observation is possible. 



As to the systematic position of Amphionides Zimmer offered no suggestion in his 

 preliminary account, and so far as I am aware he has not returned to the subject. Apart 

 from the obvious conclusion that it belongs to the Caridea there does not seem to be 

 much that one can say. It certainly cannot be referred to any known family of Caridea, 

 and its most salient features, namely the reduction of the legs and the extraordinary 

 development of pleopod i, are unique, not only among Caridea but also in the Decapoda 

 as a whole. Amphion and Amphionides must remain for the present as sole representa- 

 tives of the caridean family Amphionidae. 



LITERATURE ON THE AMPHIONIDAE 



Bate, C. S., 1888. Crustacea Macrura. Voyage H.M.S. 'Challenger', Zool., xxiv. 

 Boas, J. E. V., 1879. Amphion uiid Polycheles. Zool. Anz., XL, p. 256. 



1880. Studien over Decapodernas Slaegtskabsforhold. Kgl. Dansk Vid. Selsk. Skr. (6), I, p. 185. 



BouviER, E. L., 1917. Crustaces Decapodes (Macrures Marchews) provenant des Campagnes des Yachts 



Hirondelle et Princesse Alice, 1885-1915. Res. Camp. Sci. Monaco, l, p. 30. 

 Claus, C, 1876. Untersuchungen zur Erforschung der genealogischen Grundlage des Crustaceen-Systems. 

 DoHRN, A., 1870. Beitrag zur Kenntnis der Malakostraken und Hirer Larven. Z. Wiss. Zool., xx, p. 607. 

 GuRNEY, R., 1924. Decapod Larvae. Nat. Hist. Rep. 'Terra Nova' Exped. Zool., viii. No. 2, part ix. 

 KoEPPEL, E., 1902. Beitrdge sur Kenntnis der Gattung Amphion. Arch. f. Naturg., Lxviii, Bd. i, p. 262. 

 KoRSCHELT and Heider, 1892. Lehrbuch der vergleichenden Entwicklungsgeschichte der Wirbellosen 



Thiere. Heft 2. 

 Ortmann, a. E., 1893. Decapoda und Schizopoda. Plankton Expedition der Humboldt Stiftung. Kiel. 



Bd. II. 

 Milne Edwards, H., 1832. Note sur un nouveau genre de Crustaces de I'ordre des Stomapodes. Ann. Soc. 



Entom. France, i, p. 336. 

 SuND, C, 1915. Eryoneicus and Polycheles. Nature, London, xcv, p. 372. 

 WiLLEMOES-SuHM, R. V., 1876. Preliminary remarks on the development of some pelagic Decapods. Proc. Roy. 



Soc. Lond., XXIV, p. 132. 

 Zimmer, C, 1904. Amphionides valdiviae n.g. n.sp. Zool. Anz., xxviii, p. 225. 



