THALESTRIS. 133 



7. THALESTEIS SERRULATA, nov. sp. PL LIX, figs. 2 11. 



Male. Body elongated, of nearly equal thickness 

 throughout, first segment unusually small. Anterior 

 antenna short and robust. Inner branch of posterior 

 antenna 2-jointed. Posterior foot-jaw (fig. 7) very 

 strong, hand broad, sub- quadrate, outer margin 

 strongly arched, inner sinuous and fringed with two 

 .separate rows of spine-like cilia, the distal row sub- 

 crescentic and tending inwards towards the middle 

 of the hand; terminal claw stout, falciform, about 

 half the length of the hand; first joint bearing a 

 spine and three or four seta3 at the extremity of its 

 inner margin. Outer branch of the first foot much 

 more slender than the inner (fig. 8), terminating in 

 two long, slender spines, and a short seta; outer 

 margin closely ciliated, having a short seta below the 

 middle and one at the apex of the first joint ; pedun- 

 cle armed at the outer angle with a broad plumose 

 seta, and at the inner with a stout curved spine ; inner 

 branch very broad, and bearing a seta near the middle 

 of its inner margin, outer margin ciliated, terminal 

 claws two, one long and one short; these, as well as 

 the claws of the outer branch, are closely and finely 

 pectinated on the concave margins ; outer margins of 

 all the swimming-feet fringed with spines. Inner branch 

 of the fifth foot (fig. 9) short, broadly triangular, 3- 

 setose ; outer branch elongate sub-ovate, inner margin 

 ciliated, outer with three or four short and one long 



