550 AKE NORDENSTAM 
The variability within this species has been shown to be very consider- 
able. In the 6 specimens from Masatierra the females are more strongly 
sculptured than the males. In the females the dorsal tubercles on all the 
thoracic segments are usually distinct. Only in one female (length 6 mm) 
were they obscure on the Ist thoracic segment. 
In the males only the median pair of tubercles is developed on the tst 
to 3rd or 5th segment. In the posterior thoracic segments the tubercles are 
the same as in the female. The carina on the coxal plates is totally absent 
in the males, so that the 3 posterior coxal plates are slightly visible in dorsal 
aspect. 
Of the 4 tubercles on the last abdominal segment (cf. TATTERSALL 1913, 
Pl. XLIX, fig. 5) the minute posterior pair is sometimes totally absent, also 
in the females. 
Suborder Asellota. 
Fam. Janiridae. 
Genus Jaera beach 1813. 
Jaera antarctica Pfeffer 1887, Vanhoffen 1914. — Text fig. 12. 
One small specimen (male), taken together with 
Tanatis lineatus. 
Loc. Juan Fernandez, Masatierra, 30-—40 m, sand 
with calcareous algae. 
Distribution: South Georgia, (PFEFFER 1887), 
Kerguelen (VANHOFFEN 1914), Falkland Islands (taken 
by the Swedish antarctic expedition I9g0I—1903 and 
studied by the author at the Natural History Museum, 
Stockholm). 
Faera antarctica Pfeff. differs from the allied 
species aera serrata Barnard in a number of details, 
e.g. Ist pleopods of male (fig. 12). On these the rami 
are provided with 2 hollows, which probably function 

Fig. 
as receptacula seminis. first pleopods of male, X 104. 
12. Jaera antarctica, 

