STEBBING— ISOPODA 1 1 7 



Gen. GIGANTIONE, Kossmann. 



1881. Gigantione, Kossmann, Zeitschr. wiss. ZooL, vol. xxxv., p. 655. 



L887. Gigantione, Giard and Bonnier, Travaux Lab. Zool. Wiinereux, vol. v., 

 pp. 13, 74, etc. 



1900. Gigantione, Bonnier, Les Bopyridae, p. 276. 



In' the female all the segments of peraeon and first Hve of pleon are laterally 

 produced, the extensions on the right side being very considerable. First antennae of 

 female having the first joint developed into a large pad, against which the two following 

 joints appear to be flattened about at the middle, the third joint very small. The second 

 antennae five-jointed in the female, six-jointed in the male. Maxillipeds of the female 

 with principal lobe nearly circular, fringed with setules, showing no palp-like prominence. 

 Limbs of the peraeon with finger well developed in the male but almost obsolete in the 

 female. Pleopods of the female two-branched, diminishing in size successively from the 

 first to the fifth, with varying development of fringing lobules. Pleopods of the male 

 simple, ovoid, diminishing in size from first to fifth. Uropods in the female very small, 

 but with distinct peduncle and two branches, in the male each consisting of a single 

 piece larger than the preceding pleopod. 



Gigantione moebii, Kossmann, for which the genus was founded, measured in the 

 female 15 mm. It was taken at Mauritius from the branchial cavity of Ritppellia 

 vmpressa, de Haan. The pleopods of the male are figured more than twice as long 

 as broad. 



Gigantione bouvieri, Bonnier, measures in the female scarcely 3 or 4 mm. It was 

 taken off the Azores from the branchial cavity of Pilwmnus hirtellus (Linn.), var. inermis, 

 A. Milne-Edwards and Bouvier. The branches of the uropods in the female are described 

 as cylindrical, slender at the free extremity. 



33. Gigantione rathbunce, n. sp. (Plate 11a.) 



This species agrees very closely with the preliminary description of G. bouvieri, which 

 is unfortunately not accompanied by illustrative drawings. Its size, in the female not 

 quite 4 mm., agrees with that of Bonnier's species. Both differ in one respect from 

 Kossmann's generic account, in that the last pleon segment is not produced into lateral 

 lobes, but on that point Kossmann's own figures do not appear to be in accord with his 

 statement. 



In the new species eyes are visible, not only in the male, but also in the female. 

 In Pseudione hoylei, the visibility of the eyes in a female 12 mm. long is regarded by 

 Bonnier (Op. cit., p. 301)) as an indication that the specimen was not yet quite adult. 

 In the present case that inference can scarcely be drawn, since a multitude of young 

 ripe for discharge were in the Epicaridean stage. 



The characters of the antennae, mouth-organs, and other appendages, so far as they 

 could be made out, will be best understood by the figures. With one or two exceptions 

 they do not appear to offer any solid specific characters. Concerning the uropods of the 

 female Bonnier says that in his species they are in accord with the generic character, 



