567 



armed with sparse setae; the 3rd-7th segments together are shorter than 

 the 2nd segment. The 2nd segment of pereopods VI is similar to that 

 in T. forcipatus but its posterior margin finely denticulate in the middle 

 part; the distal process of the 4th segment reaches the middle of the 

 5th. Pereopods VII consist of a 2nd segment in which the distal end is 

 not narrowed but smoothly rounded, and a very short 3rd segment, not 

 completely separated from the 2nd and in the shape of a small tubercle. 



The rami of the uropods are lanceolate with denticulate margins and 

 the endopodites are free. The telson is narrower than in T. forcipatus and 

 longer than the last urosomite. 



Distribution: Known from the Arafura Sea ( surface catches) and 

 the environs of New Zealand, Hawaii Islands, California bay. 



5. Genus Amphithyrus Claus, 1879 



Claus, 1879a: 4; 1887: 31; Stebbing, 1888: 1485; Spandl, 1927: 246; 

 Bowman and Gruner, 1973: 55. 



Very small animals, 3-5 mm in length. 



The body is high and compact and the pereon much shorter than 

 the pleon. The head is short and high, anteriorly smoothly rounded, and 

 the same shape in females and males. The body surface of all species 

 except A. glaber is covered with a reticulate or striate sculpture. The 

 basal segment of antennae II in males is short, its anterior margin straight, 

 and the posterior markedly bulged; the lst-3rd segments of the flagellum 

 are approximately the same in length but the 4th somewhat shorter. 



Pereopods I and II are identical in structure, weak, and have chelae; 

 the 2nd segment is barely broadened distally; the distal process of the 5th 

 segment is pointed, narrow, and has smooth margins; the 6th segment 

 has a pointed denticle on the posterior margin; the claw has a broad base 

 and is bent backward. Coxal plates V have a process on the inner side. 

 The 2nd segment of pereopods V is elongated-oval with a projection 

 in the distal part; the 3rd segment is attached subterminally at the base 

 of the projection: the 3rd-7th segments together are not shorter than 

 the 2nd segment; the 4th-6th segments have a very finely denticulate 

 anterior margin. The 2nd segment of pereopods VI is represented by a 

 plate of complex shape, differing from the analogous segment in the 

 other genera of the family: the anterior margin has a notch close to the 

 base, the posterior margin is uniformly bulged, and the distal margin 

 also has a notch, due to which the segment appears twin-peaked; the 4th 

 segment has a distal process; the 4th and 5th segments have a denticulate 

 anterior margin; the 6th segment is very narrow and weak; the claw is 

 rudimentary and not pointed. 

 458 The rami of the uropods are lanceolate and the endopodites and 



exopodites equal in length. The endopodite of uropods III is generally 



