482 THE VOYAGE OF H.M.S. CHALLENGER. 



uniarticulate. First pair of antennae with two flagella. Second with a large scaphocerite 

 and all the joints of the peduncle articulating. Mandibles without a psalistoma or 

 synaphipod. First pair of gnathopoda without a dactylos, and the propodos reduced to 

 a rudimentary condition. ' Second pair having neither dactylos nor propodos. First 

 pair of pereiopoda robust and subchelate ; second pair slender, chelate or simple, having 

 the carpos uniarticulate ; third slender and styliform ; fourth and fifth simple and robust. 

 Pleopoda biramose ; rhipidura well developed. 



Crangon, Fabrieius. 

 Crangon, Fabricius, Suppl. Entoni. Syst., p. 410. 



Rostrum short, not longer than the ophthalmopod, and dorsally flattened. 



Ophthalmopoda extremely short, orbicular. 



First pair of antennae furnished at the base with a broad, flattened stylocerite, and 

 terminating at the extremity in two short flagella. 



Second pair of antennas having a broad scaphocerite and a long slender flagellum. 



First pair of pereiopoda robust, subchelate ; second pair slender and chelate ; third 

 pair slender, subequal in length to the first, and terminating in a sharp styliform 

 dactylos. The two succeeding pairs are more robust than the second and third, and 

 terminate in a long and flattened dactylos. 



The branchiae consist of four pleurobranchial plumes and one small arthrobranchial 

 attached to the articulation of the second pair of gnathopoda, which also carries a 

 mastigobranchial plate reduced to a rudimentary condition ; one of the latter also exists 

 on the first pair of gnathopoda in a small but less rudimentary form, and a small 

 branchial plume is attached to the membranous articulation. The entire arrangement 

 may be shown in the following table : — 



Pleurobranchi*, . . . 1 I 1 1 



Arthrobranchia?, . . . r ■ 1 



Podobrancbisc, . . . 



Mastigobranchise, . . . 1 1 



li i k 1 m n o 



I have accepted the genus as restricted by Mr. J. S. Kingsley in the memoir ' in 

 which he revises the genus as known to the earlier carcinologists. There can be no 

 doubt that Leach, 2 Westwood, 3 Hailstone, 4 and more recently Kinahan, 5 felt that a divi- 

 sion of the genus must take place, and in this country the separation would sooner have 

 been made, had not Bell, in his work on the British Stalk-eyed Crustacea, reunited 



1 Proc. Acad. Nat. Sci. Philad., p. 411, 1S79. 2 Malacos. Decap. Brit. 



3 Mag. Nat. Hist., vol. viii. p. 266, 1835. 4 Mag. Nat. Hist., vol. viii. p. 261, 1835. 



5 Trans. Boy. Irish Acad., vol. xxiv. p. 45, Science, 1871. 



