426 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



Head twice as wide as long, L mm. :3 nun., with the untcrior mar- 

 gin sinuate on either side of a small median point. Eyes dorsally 

 situated, with the sides of the-head expanded. Lateral margins entire. 

 The first pair of antennas have the basal article large and expanded; 

 the second article is as long as the first article and half as wide; the 

 third is short, about half as long as the second. The flagellum is com- 

 posed of seven articles, and extends almost to the end of the fourth 

 article of the peduncle of the second pair of antenna 1 . The second 

 antennae have the first two articles short and subequal; the third is a 

 little shorter than either of the first two; the fourth article is as long 

 as the first two taken together; the fifth is one and a half times longer 

 than the fourth. The flagellum is composed of about fort} T -one arti- 

 cles. The second antenna? are about 9 mm. long and extend to the 

 posterior margin of the seventh thoracic segment. The maxillipeds 

 have a palp of five articles. The palp of the mandibles is composed 

 of three articles. 



The segments of the thorax are subequal, with lateral margins 

 straight and entire. The epimera are not evident and are not sepa- 

 rated from the segments. 



The abdomen is composed of a single segment. It is rounded pos- 

 teriorly, with a slight indication of a median lobe between the uropoda. 

 The uropoda are short, being less than half the length of the abdomen. 

 The length of the abdomen is 3 mm.; that of the uropoda is 1 mm. 

 The basal segment or peduncle of the uropoda is i mm. long. The 

 inner branch is 1 mm. long. The outer branch is a little shorter than 

 the inner branch, being about three-fourths its length. 



The first pair of legs are subchelate, with the propopus armed with 

 two triangular processes on the inferior margin. All the other legs 

 are ambulatory. 



ASELLUS ATTENUATUS Richardson. 



Asellus attenuatus RICHARDSOX, American Naturalist, XXXIV, 1900, p. 297; Proc. 

 U. S. Nat. Mus., XXIII, 1901, pp. 552-553. 



Locality. Washington Ditch, Dismal Swamp, Virginia. 



Body narrowed anteriorly, gradually increasing in width backward. 



Head narrower than the first thoracic segment, rounded at the sides 

 with margins entire and a small lobe near the base on either side; 

 front somewhat excavate for the reception of the antennae. Eyes dis- 

 tinct, lateral. First pair of antennae as long as the peduncle of the 

 second pair; first joint short and broad; second joint more slender; 

 third joint not quite as long as second joint; flagellum composed of 

 thirteen joints. Second pair of antenna? as long as the body; first, 

 second, and third joints short, about equal in length; fourth and fifth 

 joints long; flagellum multiarticulate. 



