PH^DRA ANT J QUA. 



209 



AMPHIPODA. 



NATATORIA. 



PHOX1DES. 



PH^DEA ANTIQUA. 



Specific character. Third segment of the pleon having the posterior margin 

 toothed and minutely serrated. Superior antenna? furnished with a secondary 

 appendage. Rami of the posterior pair of pleopoda equal. Telson lanceolate. 



Length ^ inch. 



Pluedra 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 antennae 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 

 antennae 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- 



