NO- 3594 SARSIELLA — KORNICKER 27 



female; bristles on 3rd and 4tli joints with short spines proximally 

 along outer margin. 



Mandible, maxilla, 5tli hmb: similar to adult female. 



Seventh limb (fig. 14c) : short stump. 



Copulatory limb: consists of 2-3 lobes, hook not developed. 



Description of male instar v (fig. 15; pi. 2e-o).— Shell: More 

 elongate and shghtly smaller than female instar V. Dimensions of 

 selected specimens are as follows: 



First antenna (fig. 15a; pi. 2e, J), eyes, and frontal organ (pi. 2o): 

 similar to female instar V. 



Second antenna (fig. 156; pi. 2e, g, h): endopodite 3-jointed (fig. 

 156): 1st, 2nd, and 3rd joints each with 2 short bristles; bristles on 

 3rd joint terminal; exopodite similar to adult female. 



Mandible (pi. 2e, i), maxilla (pi. 2j, k), 5th hmb (pi. 21), 6th limb 

 (pi. 2m), furca (pi. 2n): similar to adult female. 



Seventh limb (fig. 15(/) : short stump. 



Copulatory limb (fig. 15c): consisting of hooklike "clasping organ" 

 and large transparent lobe having medially a smaUer lobe with small 

 bristle. 



Summary of development. — Shell (fig. 2) : Bristles on the outer 

 side of the shell seem already fully developed in the embryo. Also 

 present in the embryo are 2 hirsute bristles on the posterodorsal part 

 of the inner lamella. The inner side of the caudal process of the 

 embryo was not observed, but the distribution of bristles on the outer 

 side of the caudal process is similar to that of the adult. All instars 

 have truncate posteriors somewhat similar to the adult male. In 

 lateral view, the posterior is more rounded in the adult female than in 

 the instar, and the caudal process is on the ventral margin of the shell. 

 In dorsal view, the shell is broadest in instar stages near the middle 

 of the shell, where the radial ridges intersect. In the adult female the 

 posterior of the shell is relatively broader than in instars, and in many 

 the posterior is the broadest part of the shell. 



SheUs of male instars are similar to equivalent stages of the female 

 but are slightly smaUer and more elongate. The adult male is about 

 the same height as the shell of instar V but is longer. It has a promi- 

 nant rostrum, and the posterior is truncate as in the shells of juveniles. 

 The sheU of the adult male is much smaller than the adult female. 



First antenna: In the embryo the 1st antenna is divided into about 

 8 joints by sutures. One long annulate bristle is located dorsally near 

 the middle and about 7 bristles are terminal. In instar III, the 1st 



