TANAIDACEA AND MARINE ISOPODA FROM JUAN FERNANDEZ 549 



what rounded. 2nd joint somewhat shorter than the ist, distally narrowed to 

 a broadly rounded process reaching to about Yg of the length of the 3rd joint, 

 which is a little shorter than the ist. The flagellum consists of 11 joints. 



Antennae. The first 3 joints small, subequal, together slightly longer than 

 the 4th, which is broader but about as long as (very slightly shorter than) 

 the 5th. Flagellum on both antennae somewhat incomplete; probably it is 

 normally about of the same length as the peduncle. Of the flagella there 

 remain 12 and 13 joints respectively. 



Mandibles, ist and 2nd maxillae, maxillipeds Figs. 11 b, c, d, e. 



jst pereiopods (fig. 1 1 f). Merus considerably thick with 3 spines on the 

 lower margin, one at the middle of the joint and 2 spines near the distal end. 

 Propodal joint with its lower distal corner produced into a scale-like projec- 

 tion with setae on its rounded margin. 



2nd pereiopod (fig. 1 1 g). Merus thick with 6 spines on the lower margin, 

 4 at the middle of the joint and 2 at the lower distal angle. Propodus with its 

 lower distal corner scale-like and setiferous. 



jrd pereiopod. Ischium on its lower margin with 2 short distal spines. 

 Merus thick with 5 spines, 4 at the middle of the joint and 2 at the lower 

 distal angle. Propodus with its lower distal corner scale-like and setiferous. 



The ^j. posterior pereiopods with a great number of short spines. Fig. 1 1 h 

 shows the 4th pereiopod. 



2nd pleopod. The male stylet reaches to about ^3 of the lengths of the 

 endopod. 



Uropods. Both rami reach about as far as to the end of the abdomen. 

 Inner ramus slightly broader than the outer, triangulate, with the distal margin 

 truncate. Outer ramus ovate-lanceolate, with distal end rounded. The setae 

 on the margins have mostly been lost. 



Remarks. 



This species is closely allied to, perhaps the same species as Aega 

 urotoma Barnard from the Cape of Good Hope, but the eyes are still closer 

 to each other, the distance between them being only V4~V5 of their greatest 

 diameter. The merus of the first pereiopod has, besides, a smaller number of 

 spines than in the last species. 



Fam. Sphaeromidae, 



Group Hemibranchiatae Hansen 1906. 



Genus Exosphaeroma Stebbing 1900. 



Exosphaeroma calcarea (Dana 1854), Stebbing 1914; Sphaeroma calcarea 

 Dana 1854, Dollfus 1891; Exosphaeroma Coatsii Tattersall 191 3. 



7 immature specimens, 2 males 5 females, longest specimen about 6 mm. 

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

 Distribution: Tierra del Fuegia, Falkland Islands, St. Paul (Tatter- 

 sall 1913). 



