1879.] NATURAL SCIENCES OF PHILADELPHIA. 421 



count of its habitat; the other species, 0. orientalis Stm., coming 

 from China and Japan. 



Genus Pterocaris Heller. 1 Carapax and abdominal segments 

 broadly expanded at the sides. These expansions lamellate and 

 three-lobed, corresponding one to the antennal segments, one to 

 the mandibular, and the third to the abdominal segments. Eyes 

 small, just visible in front of carapax; antennulse biflagcllate ; 

 antennae with basal scale; external maxillipeds with exopodite 

 and rudimentary epipodite. Type P. typica Heller. 



Section II. Mandibles without a Palpus. 



Genus Autonomea Risso. 2 Rostrum short, eyes prominent, 

 antennulie biflagcllate, antennal scale wanting. First pair of pere- 

 iopoda stout, chelate ; second not chelate ; carpus not annulate. 

 Type Autonomea olivii. 



o Genus Virbius Stimpson 3 Dorsum of carapax and rostrum 

 ecarinate ; antennulae biflagellate; antennal scale present. Ex- 

 ternal maxillipeds short, with exopodite. Pereiopoda without 

 epipodites. Carpus of first pair of pereiopoda excavate in front; 

 carpus of the second pair triarticulate. T3'pe Virbius acuminatus 

 (Dana sp.). 



Sub-genus Thor Kingsley.* Rostrum short ; antennulae, an- 

 tenna?, and external mallipeds as in Virbius. Carpus of first pair 

 of pereiopoda not excavate ; carpus of second pair 5-articulate. 

 Type Thor floridanus Kingsley. 



Thor floridanus Kingsle} r . (PI. xiv. fig. 6.) Specimens were 

 collected by Professor H. E. Webster at Harbor Key and Sarasota 

 Ba}', Florida. 



1 Sitzungsberichte der k. Akad. Wissenschaft. Wien. XLV. pt. i. p. 395, 

 pi. i. f. 7-18 (1862). 



2 I take the fact that the mandible of Autonomea is without a palpus from 

 Heller (Crust. Siidlichen Europa, p. 223), though in his generic diagnosis on 

 p. 2-49 he makes no mention of the mandible, but takes his description from 

 Desmarest. Heller had never seen specimens of this genus. Risso (Crust. 

 Nice, pp. 1(56-169, 1816) does not mention the mandibles. 



3 Proc. Acad. Nat. Sci. Philadelphia, 1860, p. 35. For remarks on this 

 genus, vid. Smith, Trans. Conn. Acad. v. p. 62, 1879. Garadina tenuvroa- 

 tris Spence Bate, Proc. Zool. Soc'y, London, 1863, p. 501, pi. xl. f. 4, from 

 Australia, belongs to this genus. 



4 Proc. Acad. Nat. Sci. Philadelphia, 1878, p. 94. 



