THE CRUSTACEA OE NEW JERSEY. 295 



paratively short, conical, of only three or four articulations, and 

 in male usually much more fully developed. No secondary fila- 

 ment or flagellum to first antennae. Single flagellum sometimes 

 absent, generally rudimentary, rarely well developed in female 

 and multiarticulate in male. Second antennae generally smaller 

 than first, without scale, flagellum usually rudimentary, short, 

 only biarticulate. Mandibles various, without palps. Eirst max- 

 illae with only single slender masticatory lobe. Second maxillae 

 rudimentary, as simple rounded lobes. Maxillipeds coalesced 

 at base, with generally narrow falciform epignath, Chelipeds 

 usually strong, closely applied to oral area, issue from hind part 

 of cephalosome with broad base, carpus usually broad and com- 

 pressed, and hand sometimes rather dissimilar in sexes. Second 

 pair of legs not very different from succeeding ones, rather small 

 and ambulatory. Pleopoda usually very small, with lamelliform 

 incurved rami, sometimes rudimentary or quite absent in female. 

 Uropoda not much elongated, simple or biramous. 



Rather a large family, with about fifteen genera. Most of the 

 species appear to live in tubes, which they form of mud and 

 into which they may entirely draw in their bodies. On reaching 

 the surface of the water they remain floating, without being 

 capable of reimmerging their bodies. 



Key to the genera. 



a. Five pairs of pleopoda present : uropoda double-branched. leptocheua 



aa. Three pairs of pleopoda present ; uropoda simple, short, single-branched, 



of three to seven joints. tanais 



Genus LEPTOCHELIA Dana. 



Leptochelia Dana, Amer. Journ. Sci. Art., (2) VIII, 1849, p. 425. Type 



Leptochelia minuta Dana, monotypic. 

 Paratanais Dana, Atner. Journ. Sci. Art., (2) XIV, 1852, p. 306. Atypic. 



(Type Tanias eloiigaiits Dana, Crust. U. S. Expl. Exped., 1852, p. 7g8,, 



monotypic.) 

 Dolichochelia Stebbing, Ann. Mag. N. Hist. London, (6) XVII, i8g6, p. 49. 



Type Dolichochelia forresfi Stebbing, monotypic. 



