264 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 117 



ment rarely modiiied weakly. Re of P2 and P3 sometimes more 

 strongly developed in male than in female. Rami of P5 either 

 separate or fused; male P5 sometimes a single plate (from Lang, 1948, 

 p. 281). 



Genus Euterpina Norman 



Rostrum produced into strong point. Caudal ramus somewhat 

 longer than wide. Al of female 7-segmented, without plumose setae; 

 in male prehensile, with plumose setae. Re of A2 1-segmented. B 

 of Md without setae. Mxl with rudimentary Re and Ri. Mx2 

 with small 2-segmented Ri. Mxp very slender, with long terminal 

 claw. PI with short 2-segmented rami and weak sexual dimorphism; 

 Rel with inner seta; Re2 with 7, Ri2 with 6 appendages. P2-P4 

 with 3-segmented rami; Ri shorter and more slender than Re; Rel 

 and Re2 with outer spines. B of P1-P4 without outer setae. Ri of 

 male P2 sometimes (always?) 2-segmented. Female P5 a long, 

 nearly square-cornered plate with 4 terminal spines, 1 outer spine, 

 and proximal outer seta. Male P5 fused at base, divided at tip by 

 median groove reaching halfway to base, armed with 2 terminal 

 spines on either side, 1 outer spine with seta arising at its base, and 

 proximal outer seta (from Lang, 1948, p. 285). 



Euterpina acutifrons (Dana) 



Figures 14:d-l 



Harpacticiis acutifrons Dana, 1847, p. 153. 



Euterpe acutifrons (Dana).— Dahl, 1894, p. 13.— Cleve, 1900, pp. 65-66.— Davis, 

 1950, p. 97 (table). 



Euterpina acutifrons (Dana) .— Carvalho, 1945, pp. 103-104, pi. 5, fig. 22; 1952, 

 pp. 163-164, pi. 2, figs. 85-88.— Lang, 1948, pp. 285-287, fig. 142, map 343 

 [synonomy, distribution].— King, 1950, p. 130 (table). — Grice, 1956, pp. 

 56-57.— Woodmansee, 1958, p. 256.— Deevey, 1960, p. 33.— L6gar4, 1961, 

 p. 206.— Zoppi, 1961, table 4.— Bjornberg, 1963, pp. 71-72, fig. 37. 



With the characters of the genus, which is monotypic. Length of 

 Puerto Rico specimens: female, 0.53-0.60 mm.; male, 0.46 mm. 



Distribution. — Worldwide in tropical and subtropical coastal 

 waters (see Lang, 1948, map 343, p. 1588). Although never abundant 

 in the Puerto Rico samples, E. acutifrons occurred regularly in the 

 bays and over the shelf and was the most common planktonic 

 harpacticoid. 



Family Ectinosomidae 



Body slender, usually without noticeable boundary between 

 prosome and urosome. Eye absent. PedSeg 1 fused with head. 

 Female genital segment without transverse suture. Al short, not 

 more than 7-segmented in female. Re of A2 at most 3-segmented; 



