128 U.S. NATIONAL MUSEUM BULLETIN 23 6 



Antenna and mouth parts identical with those of female. I ob- 

 tained a good preparation of the maxillule, which has been figured here 

 (fig. 42e). The praecoxal arthrite is well developed, carrying 7 spini- 

 form setae. Coxa and basis each with small endite, each with 3 

 setae. Basopodite with 3 additional setae and a small unsegmented 

 endopodite, carrying 5 setae. There is no trace of an exopodite, but 

 there is a small basal exite with a single, strong seta. 



4. Legs 1 to 4 as in female, with exception of endopodite of leg 2, 

 which is slightly transformed, as appears from reduction of number 

 of setae on 3rd endopodal segment: in female, 4; in male, only 2 

 (fig. 43e). 



5. 5th legs with short, flipper-shaped exopodite with 6 marginal, 

 short setae. No trace of external lobe of baso-endopodite (fig. 

 43/). 



Remarks. — This new species approaches Porcellidium affine Quidor 

 in many respects; it is, however, much smaller and with a more broadly 

 ovate body. The furca, in the female of the present species, is 

 cut off squarely at the end, and in P. affine it is rounded ; in the male 

 of the present species there are 6 normally haired setae along the margin 

 of leg 5; in P. affine these setae, with the exception of the more supe- 

 rior, are denticulated. 



Three individuals of the present new species were washed from 

 caulerpas off the reef ridge at the north end of Falarik in the Ifaluk 

 Atoll. 



Family Peltidiidae G. O. Sars, 1904 



Genus Peltidium Philippi, 1839 



In addition to some juvenile specimens of the type of this genus, 

 Peltidium purpureum Philippi, 1839, there are individuals of P. 

 intermedium A. Scott, 1909, and P. exiguum A. Scott, 1909. Keys 

 to the females and males of this genus have been published by Lang 

 (1948, p. 430) and Nicholls (1941, p. 391); the genus will not be 

 discussed here. 



Peltidium purpureum Philippi, 1839 



FiGUKE 45 



Peltidium purpureum Philippi, 1839, p. 131, pi. 4 (figs, 12, 13). — Vatova, 1928, 

 p. 181. — Marine Biological Association, 1931, p. 161. — Nicliolls, 1941, 

 pp. 390, 392, 393.— Dahl, 1948, p. 92.— Lang, 1948, p. 431, fig. 184 (no. 1).— 

 Marine Biological Association, 1957, p. 164. 



Material. — Loc. 638, 1 juv. specimen, 0.48 mm. Harry Sta. 41 > 

 2 juv. specimens, 0.54 and 0.55 mm. 



Description. — 'The foUomng notes are based on the specimen 

 from locality 638. Total length 0.48 mm.; greatest diameter 0.30 

 mm.; longest furcal seta 0.23 mm. 



