BOERADAILE— ON THE PONTONIIN^ 329 



it between Anchistia and Palcemonella. Both Palcemonella and Urocaris consist of 

 gracefully built species, and until recently it has generally been considered that their 

 affinities are Paleemonine rather than Pontoniine. In 1878 Kingsley founded a sub- 

 family Pontoninse for the genera Pontonia, Coralliocaris, Harpilius, Anchistia, Urocaris, 

 and Typton, together with the Euryrhynchus of Miers and Palcemonetes of Heller 

 which are certainly Palsemoninse and have been treated as such by all subsequent 

 authors. In 1879, however, Kingsley treated the members of the Pontoninse merely 

 as a section of his Palsemoninae. In 1888 Bate raised them to the rank of a 

 family — the Pontoniidae. In 1890 Ortmann made considerable contributions to our 

 knowledge of this family, and in 1899 he added to it the Hymenocerinse, placing 

 its original members in a subfamily Pontoniinse. The true affinities of Hymenocera, 

 however, are not represented by this arrangement". In 1898 I revised the Pontoniidae, 

 establishing a new genus Aiichistus for some species intermediate between Pericli- 

 menes and Pontonia. Since then Nobili has founded in 1902 the genus Coutierea, 

 and in 1906 Stegopontonia, both related to Coralliocaris. Ancyclocaris, established 

 in 1902 by Schenkel for a prawn which is now known to shelter under the pro- 

 tection of a sea anemone, was connected with the Pontoniidae by Nobili in 1906. 

 In 1907 I reverted to the view that the Pontoniinae should rank as a subfamily 

 of the Palaemonidae. Finally, Sollaud, in an illuminating article (1910), discussed the 

 characteristic features of the Pontoniidae, and definitively included among them the genera 

 Palcemonella and Urocaris. In the present ,paper five new genera — Urocaridella-f, 

 Pontoniopsisf, Periclimenreusf, Pontonides, and Harpiliopsis — are proposed, and four 

 subgenera established within the genus Periclimenest- 



The history of the Pontoniinse as a unit of classification may be summed up as follows : 



Subfamily Pontoniinae Kingsley, 1878. 



Pontonincs Kingsley, Bull. Essex Institute, x. p. 53 (1878). 



PontoniidcB Bate, " Challenger" Macrura, p. 927 (1888). Ortmann, in Spengel; Zool. 

 Jahrb. Syst. v. p. 460 (1890). Borradaile, Ann. Mag. Nat. Hist. (7), ii. p. 376 (1898). 



Bathbun, Bull. U. S. Fish. Comm. xx. ii. p. 120 (1901). Sollaud, C. R. Ac. Sci., 

 cli. p. 1158 (1910). 



Pontoniiym Ortmann, Bronn's Thierreich, v. ii. pp. 1124, 1130 (1899). Borradaile, 



Ann. Mag. Nat. Hist. (7), xix. p. 472 (1907); lb. (8) xv. p. 206 (1915). 



The Organization of the Pontoniinge. 



The connection between structure and mode of life is very cleaidy shown by the habit 

 of body of Pontoniinae. In Urocaridella (Plate 53, fig. 2) and Urocaris, whose members are 

 probably all free swimmers, the body is slender and strongly compressed, with a very long 

 sixth abdominal segment. In Palcemonella (Plate 53, fig. 5) and Periclimenes (Plate 52, 

 fig. 1), which wander, with an activity that probably varies from species to species, over 



* See pp. 405, 408, 410 in this volume. 



t Preliminary descriptions of these genera have been published in the Annals and Magazine of Natural 

 History for February, 1915. 



:|: Marygrande Pesta, 1911, is not, in my opinion, distinct from Anchistus. 



SECOND SERIES— ZOOLOGY, VOL. XVIL 42 



