REPORT ON THE AMPHIPODA. 805 



preheusiles." To it he assigns the genera Lepidactylis, " Potitiporeia ," Amjielisca, 

 Protomedeia, Aora, in one division, and Phoxus by itself in a second. In 1857 ' Spence 

 Bate made the Pontoporeidae the fourth subfamily of the Gammaridse, with the genera 

 Westwoodia, Kroyera, Phoxus, Sulcator. In the same year he changed the name of 

 the subfamily to Phoxides, on the ground that Kr0yer's Pontoporeia belonged to the 

 Lysianassides. In 1862 he placed in the subfamily Phoxides the genera Phoxus, 

 Grayia, Westivoodilla, (Edicerus, Monoculodes, Kroyera, Amphilochus, Darwinia, 

 Lafystius, Guerinia, Lepidactylis, Sulcator, Urotho'e, Liljehorgia, Phsedra, Proso- 

 poniscus, Isasa, Iphimedia, Otus, Acanthonotus. Lilljeborg in 1865 made the 

 " Pontoporeina, Dana," the second subfamily of the Gammaridse, with the genera 

 Bathyporeia, Stegocephalus, Pontoporeia, and the " Phoxina (Phoxides, S. Bate) " 

 the fourth subfamily, with the genera Phoxus, Urotho'e, Tiron, by implication therefore 

 including Syrrho'e also. Boeck in 1870 made the " Pontoporinse, Dana," the second, 

 and the " Phoxinas, Spence Bate," the fifth subfamily of the Gammaridse. In 1872-6 he 

 placed the two subfamilies side by side, as respectively the second and third subfamilies 

 of the Gammaridaa, the Pontoporinse receiving the genera Pontoporeia, Priscilla, 

 Argissa and Bathyporeia, the Phoxinse containing the genera Phoxus, Harpinia, 

 Sulcator, Urotho'e. Gerstsecker in 1866 places Stegocephalus, Pontoporeia, and Bathy- 

 poreia in the second division of the " Lysianassina (et Stegocephalina), Dana," sinking 

 the names Andania, Priscilla, and Argissa as synonyms, while to the "Phoxina 

 Sp. Bate," he gives much the same extension as Spence Bate gives to the Phoxides. 

 Sars in 1882 established, without defining, the Pontoporeiidae, as fourth family of the 

 Gammarina, placing in it the eight genera which Boeck had divided between the 

 Pontoporinse and Phoxinse. From the definitions given by Boeck of the two groups, 

 the following characteristics may be taken as belonging to both :— 



Up2)er Lip apically rounded. 



Mandibles apically dentate, strong, with a powerful molar tubercle, palp triarticulate. 



Upper Antennae short, with an accessory flagellum. 



Third, Fourth, and Fifth Perseopods of various forms in the different genera, 

 especially the third pair; the fourth pair generally longer than the third or fifth, 

 sometimes much dilated ; the fifth pair with the first joint much dilated. 



The Uropods biramous. 



Telson more or less cleft. 



The first four pairs of side-plates generally large, plumose on the lower margins. 



In 1885 Sars makes the Phoxidse the second family of the tribe Gammarina, placing 

 in it the genera Phoxus, Harpinia and Urotho'e, but without otherwise indicating the 

 limits of the family. 



' See also Note on Spence Bate, 1856 (p. 230). 



