TANAIDACEA AND MARINE ISOPODA FROM JUAN FERNANDEZ 20 
on 
of the distal setae on the carpus are visible, 2 of them being hidden by the 
propodus. 
Pleopods normal. 
The wropods consist of 8 joints (subadult male, length 5 mm) and 6 joints 
(immature specimen, length 2.3 mm). 
Remarks. TZanats marmoratus very much resembles the previously de- 
scribed species /. “toralts Vanhoffen and 7. gracilis Heller, of which two 
species VANHOFFEN (1914) says that immature specimens cannot with certainty 
be distinguished from each other. 
The new species shares with 7. /foral/s Vanh. the possession of very 
strong chelipeds and, like that species, is of a bluish-grey colour. It differs, 
however in the greater number of joints in the uropods in specimens of about 
equal size. 
From the figures and description of 7. gracz/zs Heller made by HELLER 
(1865) and by STEBBING (1905), 7. marmoratus only differs in its anteriorly 
narrower Carapax, a character which in 7. sarmoratus is distinct in the small 
specimen also. The difference could be explained as being of a secondary 
sexual nature, but such a sexual difference is not known in the genus. 
From 7. gracilis, as described by VANHOFFEN (1914), 7. marmoratus 
differs very much more in its very broad chelipeds. One cannot, however, be 
quite sure that 7. gracilis of VANHOFFEN is the same species as the original 
one described by HELLER. Indeed TATTERSALL (1921) has pointed out that 
T. gracilis Vanhoffen cannot at present be separated from 7. Oh/zni Stebbing. 
That, on the other hand, 7. gracz/zs is identical with 7. spongzcola Bar- 
nard is the opinion of VANHOFFEN (1914) and of BARNARD (1925), a view 
which is very probable, at least as regards the specimens seen by VANHOFFEN. 
If this is correct 7. Ohlinz is probably a distinct species, in view of the 
differences in the mouth-parts between this species and 7. spongicola. 
Tanais (Avatanazs) lineatus n. sp. — Pl. 20, figs. 2, 3; text figs. 3, 4. 
25 immature specimens of a length varying between 2.5 and 4 mm. 12 
females. 13 males. 
Loc. Juan Fernandez: Masatierra, 30—40 m, sand with calcareous algae. 
The two sexes are separated by their different shapes of body. 
The femates (Pl. 20, fig. 3) are subcylindrical. The ventral side is slightly 
vaulted and their height is about %, or more of their width. The thoracic 
segments have the lateral margins strongly convex, and the 5th, 6th and 7th 
are longer than they are broad. 
The males (Pl. 20, fig. 2) are broader and generally a little shorter. They 
are ventrally flat and their height is about 1/,; of their width. The lateral mar- 
gins of the thoracic segments are straighter, and the 5th, 6th and 7th thoracic 
segments are broader than they are long. 
Description. 
Body about 8 times as long as it is broad (in male only about 5—6 times). 
