ORDER PHYLLOPODA — APUS. 61 



ORDER VII. PHYLLOPODA. 



Shield delicate, of a single piece, free behind. Two corneous mandibles, semicylindrical, 

 without palpi ; the tip compressed, straight and dentate. First pair of feet oar-shaped, 

 and terminating in articulated setae ; the others branchial, and composed of more than 

 sixty pairs. 



(EXTRA-LIMITAL.) 



Genus Aptis, Scopoli. Head confounded with the shield, which is soft, subcrustaceous, rounded, oval, 



emarginate behind. Tail short, jointed, ending in two long threads. Antenna? two, short, 



simple. Three sessile, unequal eyes. 



A. caudatus. (Binoculus id. Say, 1. c. Vol. 1, p. 437.) Body subovate. Antenna? more than half 



as long as the body. Tail of three segments, half as long as the body ; second segment transversely 



quadrate, narrower than the first in the female, elongated and attenuated in the male. Length, 



0*01. Florida. 



Obs. I place this species here with some hesitation. It is probable also that near this will be 

 placed that singular crustaceous fossil described in the Annals of the Lyceum of Natural History 

 of New- York, Vol. 1, p. 375, pi. 29, under the name of Eurypterus remipes. Milne-Edwards 

 appears disposed to think that it forms a passage between the Isopoda and Branchiopoda. 



