686 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



124. Genus LIGIDIUM Brandt." 



Body oblong; attenuated behind. 



First pair of antenna 1 projecting in front; terminal joint small, artic- 

 ulated at one angle of middle joint. Mandibles without ciliated lappet 

 behind cutting part. Palp of maxillipeds with articles not much 

 expanded; epignath narrow, linguiform. 



Abdomen abruptly narrower than thorax; terminal segment with 

 the lateral parts not developed. 



Uropoda with the peduncle produced at the inner post-lateral angle 

 in a conical process, to which the inner branch is articulated. Branches 

 unequal in length; inner branch provided with two long and slender 

 terminal bristles. 6 



ANALYTICAL KEY TO THE SPECIES OF THE GENUS LIGIDIUM. 



a. Inner branch of the uropoda furnished with two long apical bristles. 



b. Inner branch of the uropoda not extending to the tip of the outer branch. 



Lit/ldium hypnorum (Cuvier) 



I/. Inner branch of the uropoda longer than the outer branch and surpassing it. 

 c. Inner process of the basal article of the uropoda one-fourth as long as the 

 outer branch. Inner branch one-sixth part longer than the outer branch; 

 terminal filaments equal to half the length of the outer branch. 



Ligidium tenue Budde-Lund 



c'. Inner process of the basal article of the uropoda six or seven times shorter than 

 the outer branch. Inner branch one-third part longer than the outer 

 branch. Terminal bristles equal to one-third the outer branch in length. 



Ligidium longicaudatum Stoller 



of. Inner branch of the uropoda not furnished with apical bristles, but tipped with 

 setae Ligidium gracilis (Dana) 



LIGIDIUM HYPNORUM (Cuvier). 



Oniscus hypnorum CUVIER, Jour. d'Hist. Nat., II, 1792, p. 19, pi. xxvi. 



Ligidium hypnorum BUDDE-LUND, Naturh. Tidsskrift (3), VII, 1870, p. 225. 

 STUXBERG, Ofversigt Vetensk. Akad. Forhandl., 1875, No. 2, p. 48. BUDDE- 

 LUND, Crust. Isop. Terrestria, 1885, pp. 254-256. UNDERWOOD, Bull. 111. 

 State Lab. Nat. Hist, II, 1886, p. 361. RICHARDSON, Proc. U. S. Nat. Mus., 

 XXI, 1899, p. 867; Ann. Mag. Nat. Hist. (7), IV, 1899, p. 335; American 

 Naturalist, XXXIV, 1900, p. 306. 



Localities. California; Niagara in Canada; also Sweden, Den- 

 mark, Germany, France, and the British Isles; Constantinople and 

 "Chersonese Taurico" (Budde-Lund). Found in moist places. Budde- 

 Lund thinks that the species found in North America and recorded by 

 Stuxberg as the above is not likety the same, or rather he doubts that 

 this species occurs in North America. I have never seen an}* speci- 

 mens of this species. 



From the description and figures which Prof. S. J. Holmes gives of Styloniscus 

 gracilw Dana, the species ought to be referred to the genus Ligidium Brandt. The 

 genus Euphilosciti Packard is probably a synonym of Ligidium. 



&See Sars for characters of genus, Crust, of Norway, II, 1899, p. 157, and Budde- 

 Lund, Crustacea Isopoda Terrestria, 1885. 





