203 



The uropods are weakly armed. Uropods I are denticulate on the 

 entire anterior margin; the denticles on the basi- and endopodite may 

 vary in size; the posterior margin is smooth. Uropods II are coarsely 

 denticulate in the distal part of the posterior margin. In uropods III the 

 inner margin of the exo-and endopodite is denticulate. The telson is 

 roundish-triangular with rounded or acute tip. 



Notes: The length ratios of the pereopod segments are subject to 

 fairly significant individual variation, which served as the basis for 

 describing several independent close species, which later were combined 

 into a single fairly variable species. 



The two rare species — S. similis and S. nana — described below are 

 close to S. tullbergi. Specimens are known which are intermediate in 

 several characters to all these species. However, the paucity of material 

 for S. similis and S. nana and the fact that "transitional" specimens could 

 nonetheless be reliably included under any one of these species, allows us 

 for the present to consider the three as independent species. Scina setig- 

 era, S. excisa, and S. damasi have much in common with S. tullbergi. 

 These six species constitute a single group, tullbergi, which distinctly 

 differs from other species of Scina. 



Distribution: S. tullbergi is the most common surface species of 

 scinids of the warm-water regions of the oceans. It is known from 

 the tropical Atlantic (from 39°44' N, 28°53' S to 33°53' S, 9°26' E), 

 Mediterranean Sea, from many parts of the Indian Ocean where its south- 

 ern most report relates to 42° 20' S., 121° 25' E and from the Pacific 

 Ocean where it is found from Cape Horn and the Tasman Sea, south to 

 San Diego and north to 20° N. It is found in catches from 0-50, 50-100, 

 100-200, 200-500 m and in horizontal catches from the near-surface 

 layers (40-50 m) to depths of 625, 660, and 720 m. 



21. Scina similis Stebbing, 1895 (Fig. 82) 



Stebbing, 1895: 362; Stephensen, 1918: 29; Chevreux, 1919: 15; 

 Wagler, 1926: 390, 1927: 102; Vinogradov, 1964: 138. 



Length or sexually mature specimens 2.5-3.5 mm. 



The body is smooth and without keels. Antennae I are strong, equal 

 in length to the pereon or just slightly shorter than it. The mouth cone is 

 small. The outer lobes of the maxillipeds are long, oblong-oval, tapering 

 distally, with an acute tip; the inner lobes are very short, with two apical 

 setae. 



Pereopods I-IV are the same as in S. tullbergi; the 2nd segment 

 of pereopods V is broad and armed on the posterior margin with long, 

 curved denticles; the anterior margin of the segment is smooth, with one 

 or two denticles only at the base of the short distal process; the 4th seg- 

 ment is almost the same length as the 2nd, and the 5th segment is almost 

 half its length; the thin 6th segment usually constitutes 3/4-5/6 the length 



