536 Ake nordenstam 



1st pleopod (fig. 5 e). Basipod subrectangular, with the inner distal angle 

 not produced. Exopod 2-jointed with the end narrowly rounded. 



2nd pleopod (fig. 5 f). Endopod 2-jointed, 2nd joint about ^3 as long as 

 the first. Exopod obscurely 2-jointed. 



-^rd — §th pleopods. Like the second. 



Uropods (fig. 5 g). 1st joint of endopod with a longitudinal row of setae 

 on the lateral margin, 2nd joint a little ovate, but only slightly longer than it 

 is broad, reaching slightly further than telson, dorsally concave, ventrally con- 

 vex. Exopod with outer margin a little sinous near apex. 



Paranthura gracilipes n. sp. — PI. 20, fig. 5; text fig. 6. 



One female with empty marsupium, length about 9 mm, 



Loc. Juan Fernandez, Masatierra, 30—40 m, sand with calcareous algae. 



Description. 



Head about V3 longer than it is wide. The anterio-lateral corners rounded, 

 scarcely more produced than the small triangulate rostrum. Anterior margin 

 bisinuate. Eyes large rounded, dark brown, composed of about 22 ocelli. 



Thorax. The thoracic segments decrease very slightly in length to the 6th. 

 The 7th segment is abruptly shorter and a little shorter than half the length 

 of the 6th. Impressed line anteriorly on the last 3 thoracic segments absent. 



The marsupium consists of 4 pairs of large and thin oostegits and covers 

 the 2nd, 3rd, 4th, and 5th segments, and the greater part of the 6th segment. 

 The ventral side of first segment is slightly carinated, on the 7th slightly vaulted; 

 the other segments have a longitudinal furrow inside the marsupium. 



Abdomen. The 5 anterior segments increase slightly in width posteriorly. 

 Besides the telson, there are 6 segments visible; the 6th is situated between 

 the bases of the uropods but is not as broad as the other. The segments are 

 distinctly limited also dorsally. The ist abdominal segment is about twice as 

 long as the 2nd. The following 5 segments are of about equal length. The 

 6th segment (fig. 6 f) has its posterior margin cleft. 



Telson (fig. 6 f ) sublanceolate, a little narrower at the base, with lateral 

 margins slightly convex, distally narrowly rounded but with the small setiferous 

 apex truncate. Dorsal side somewhat convex, ventral side slightly convex 

 with a faint and narrow longitudinal carina in the middle line. 



Colour faintly yellow, with scattered, dark, rounded dots. 



Antennulae are about as long as the head and reach to about half the 

 length of the ist joint of the flagellum of the antennae. First joint about 

 twice as long as it is broad and about as long as the 2nd and 3rd joints 

 together; 2nd joint slightly shorter than 3rd. The flagellum is about as long 

 as the peduncle (slightly shorter) and consists of 4 — 6 joints (5 or 6 on the 

 right, only 4 on the left antennula). The joints decrease in size from the first 

 to the last. 



Antennae, ist joint about half as long as it is broad and about 73 as long 

 and narrower than the 2nd. Second joint with the median margin straight. 



