PELEDRA ANTI QUA. 
209 
AMP HI POD A. PIIOXIDES. 
NATATORIA. 
Specific character. Third segment of the pleon having the posterior margin 
toothed and minutely serrated. Superior antennae furnished with a secondary 
appendage. Rami of the posterior pair of pleopoda equal. Telson lanceolate. 
Length ^ inch. 
Phcedra antiqua. Spence Bate, Quart. Journ. Greol. Soc. 1858, p. 137, 
pi. 6, fig. 8. Cat. Crust. Amph. Brit. Mus. p. 120, 
pi. 21, fig. 2. 
The head is anteriorly produced to a central point. 
The third segment of the tail has the inferior half of 
the posterior margin minutely serrated, the limits being 
bounded by a prominent tooth above and below. The 
superior antennse have the first joint of the peduncle 
broader and longer than the second, and the second more 
so than the third, whilst the third is scarcely longer, 
though broader, than the first articulus of the flagellum ; 
the secondary appendage consists of a single articulus, 
but the remainder may be broken away. The inferior 
antennse have the joints of the peduncle that remain in 
the specimen before us as stout as those of the first joint 
of the superior. The coxae of the first four pair of 
legs are deeper than those of the three posterior. The 
three posterior pairs of legs are subequal. The poste- 
