Ostracoda and Foraminifera of Tidal Rivers. 25 
the middle, and ag m less than the height. Animal 
unknown. Length ;'; inch. 
Hab. Thames estuary. 
Genus POLYCHELES, nov. gen. 
Shell fragile, structureless. R oblong, higher behind 
than in front ; lucid Jgs ten to twelve, linear-oblong or 
wedge-shaped, arranged in a subradiate manner in front of 
the centre of the yes Seen dee the side, compressed, 
n 
small slender teeth ; first maxilla mU of a broad, 
ee basal portion, from the distal border of which 
spring eight long and strong curved sete, and from its an- 
terior hecate a long biarticulate digit, "which terminates 
in four curved claws, two of which are long, and two short; 
second maxilla consisting of four digits, the anterior larger 
and stouter than the rest, biarticulate, and terminating in 
four slender claws, the other three Tn e opted, small and 
slender, each terminating in two long sete; at the base a 
large branchial plate surrounded by Tasa thirty plumose 
processes. First pair of legs small, almost rudimentary, 
four-jointed, second and third five-jointed, the third much 
the longest, its last joint armed with two strong curved 
claws and one shorter seta; the longer of the two vta 
twice the length of the shorter. Abdomen ending in 
short conical process. Copulative organs of the male of 
complex structure, the basal portion (on each side) consist- 
ing of a subrhomboidal acuminate lamina, the apical portion 
of an irregularly shaped plate produced laterally into an 
aliform process, and on the distal margin into a short, 
strong hook. Female probably viviparous. 
Polycheles Stevensoni, nov. sp. (Pl. VII. figs. 1-7, 
and Pl. X. figs. 4-14.) 
Carapace of the female, as seen from the side, oblong, depressed 
in front, height equal to more than one-third of the length ; 
extremities obliquely rounded, anterior narrowed, posterior 
broad and obtuse: superior margin nearly straight, 
downwards in front of the middle ; inferior slightly pedes 
in the middle. Seen from above, ovate-acuminate, widest 
near the posterior extremity, greatest width about equal to 
