409 



the 2nd segment is almost five times longer than wide; the 5th segment is 

 roughly the same length as the 2nd and twice as long as the 6th; the claw 

 is weakly curved and 1/4 the length of the 6th segment. Pereopods V-VII 

 have similar proportions, slightly shorter than pereopods III-IV. The 2nd 

 segment of pereopods V-VI is roughly five times longer than wide, in 

 pereopods V equal to, and in pereopods VI- VII considerably longer 

 than the next three segments together. The 6th segment of pereopods V 

 is shorter than, and in pereopods VI-VII slightly longer than half the 

 length of the 5th segment; the claw is 1/3 the length of the 6th segment. 



The pleon is slightly shorter than the last four pereon somites 

 together. The basipodites of the pleopods are considerably longer than 

 the rami and are armed with six copulative hooks aligned in a straight 

 row. The urosome is longer than the last pleon somite. Urosomite I is 

 somewhat broader and slightly longer than the last (geminate) one, the 

 maximum width of which is almost twice its length. Uropods I pass 

 beyond the tips of the rami of uropods III; the basipodite is almost 

 twice broadened distally compared to the proximal part, its inner margin 

 is denticulate; the length of the rami is more than half the length of 

 the basipodite; the rami are equal in length, lanceolate, and strongly 

 denticulate. Uropods II reach the middle of the rami of uropods III; 

 the basipodite is considerably narrower than that of uropods I and less 

 broadened distally, its length four times its maximum width and twice the 

 length of the rami, its inner margin denticulate; the rami are elongated- 

 lanceolate and denticulate; the exopodite is slightly longer than the 

 endopodite. The basipodite of uropods III is broad, narrowed only at 

 the place of articulation, its length roughly twice its width and more 

 than twice the length of the rami, its inner margin denticulate; the rami 

 are elongated-oval and wide-set; the endopodite is denticulate on both 

 sides, the exopodite only on the inner margin. The telson is roundish- 

 trapezoid, its length less than its width and less than 1/3 the length of 

 the last urosomite. 



Distribution: Known from the waters of southern California, 

 although the species is probably widely distributed. 



2. Dairella latissima Bovallius, 1887 (Fig. 177) 



Bovallius, 1887a: 24; 1889: 336; Vosseler, 1901: 51; Stephensen, 

 1924:- 112; Reid, 1955: 19.— bovallii Stebbing, 1888: 1343. 



Body length 6-8 mm. 



The integument is very thin, sometimes with punctate reddish chro- 

 matophores on the sides of the pereon and pereopods III-VII. The head 

 is broad (width much more than height, and height slightly more than 

 length); it is slightly longer than the first geminate somite of the pereon 

 but shorter than it and the next somite together. The upper group of 

 ocelli occupy the dorsal surface of the head and descend to the lateral; 



