AMPHIPOD GENUS PARATHEMISTO BOWMAN 375 



with no sign of dorsal spines, and with coarse serrations on the inner 

 ramus of uropod 3. P. gaudichaudii is characterized by larger size (up 

 to 18 mm.), very distinct dorsal spination in adults, and the lack of 

 serration along the inner margin of uropod 3 inner ramus aud peduncle. 

 In P. gracilipes the peduncle of uropod 3 of the very largest specimens 

 appears serrulate when viewed under very high power, but is not at all 

 comparable to that of P. australis. The serration of uropod 3 inner 

 ramus is poorly developed in the female of P. gracilipes. 



Parathcmisto (Euthemisto) gracilipes (Norman) 



Figures \\,a-i; 14-15; 16,6 



Hyperia gracilipes and (?) //. oblivia Norman, 1869, p. 287. 



Themisto gracilipes (Norman), Stephensen, 1924, pp. 97-103, figs. 39-42 [lit. and 



syn.]; 1949, p. 54.— Pirlot, 1929, p. 128.— Candeias, 1934, pp. 4-5, fig. 4. 

 Parathemisto (Euthemisto) gracilipes (Norman), Barnard, 1930, p. 421. — 'Hurley, 



1955, pp. 153-161, figs. 133, 158, 176, 178. 

 [?] Parathemisto sp. (12), Yamada, 1933, p. 8, pi. 2, fig. 12a-e. 



Diagnosis: Total length of adult, excluding antennae, 4-7 mm., 

 rarely up to 9 mm. (Stephensen, Mediterranean and Atlantic speci- 

 mens); 6.5-14 mm. (Hurley, New Zealand specimens); 4.1-5.6 mm. 

 (specimens from Tusima Straits and Eastern Sea). Only slight ten- 

 dency to dorsal spination. Carpus of P2 extends about two-thirds 

 along propodus, has one stout end spine. Uropod 3, inner ramus 

 pectinate on both margins; inner margin of peduncle finely toothed 

 in male (teeth very inconspicuous or absent in female). 



Remarks: The above diagnosis is based largely on that of Hurley 

 (1955, p. 153), who has studied abundant material of P. gracilipes, 

 P. gaudichaudii, and P. australis from New Zealand waters. I have had 

 at my disposal a limited number of specimens from two surface- 

 plankton tows— one made in Tusima Straits (34°20.7' N., 130°47.3' 

 E.) and the other in the East China Sea west of Kyusyu, Japan 

 (32°06.4' N., 128°57.0' E.), kindly sent to me by Zinziro Nakai. In 

 addition, Won Tack Yang sent me three lots from off the southern 

 coast of Korea. The characters which Hurley regards as diagnostic 

 for P. gracilipes are found in these specimens. The Japanese speci- 

 mens are small; two adult females measure 4.8 and 5.4 mm., and 

 eight adult males range in length from 4.1-5.6 mm. and average 4.9 

 mm. The setal armature of the pereopods resembles Stephensen's 

 (1924, figs. 39-41) rather than Hurley's drawings (1955, text-figs. 8-9). 

 This fact may be attributed to the larger size of the New Zealand 

 specimens. 



In the Japanese specimens the serrulations of the inner margin of 

 the male and female uropod 3 peduncle are barely discernible under 

 high (X440) magnification, even less evident than that figured by 



O405S0— 60 3 



