ISOPODS OF NOKTH AMERICA. 



401 



FIG. 448. ERICHSONELLA AT- 

 TENUATA (AFTER HAR- 



GER). X 3. 



than the second. The first pair of antennae extend to the middle of the 

 third article of the peduncle of the second pair of antennae. The first 

 article of the second antennae is short and inconspicuous in a dorsal 

 view; the second article is long, about three times longer than the first; 

 the third is about one and a half times longer 

 than the second; the fourth is about one and a 

 half times longer than the third; the fifth is a 

 little shorter than the fourth. The flagellar ar- 

 ticle is a little longer than the fourth peduncu- 

 lar article. The second antennae are 7i mm. 

 long, or longer than half the en- 

 tire length of the body. The palp 

 of the maxillipeds is composed of 

 four articles. 



The first segment of the thorax 

 is a little shorter than any of the 

 others except the seventh, both of 

 which are 1 mm. long. The sec- 

 ond, third, fourth, and fifth seg- 

 ments are subequal and each is 



about H nun. in length. The sixth segment is about li 

 mm. long. The epimera are distinctly separated on all 

 the segments, including the first. They are very small, 

 almost inconspicuous, placed in the first three seg- 

 ments on the lateral margin anterior to the median trans- 

 verse line. In the fourth segment they occupy the middle of the lat- 

 eral margin. In the last four segments they are placed below the 

 median transverse line. They give the segments a rather angular 

 appearance. 



The abdomen is composed of a single segment. About one-third 

 the distance from the base to the posterior extremity is a small lateral 

 process on either side. Below these processes the sides of the abdo- 

 men are nearty parallel to a point about i mm. from the extremity, 

 where they converge to a rounded apex. 

 The legs are all ambulatory with bi-unguiculate dactyli. 



ERICHSONELLA FILIFORMIS (Say). 



Stenosoma filiformis SAY, Jour. Acad. Nat. Sci. Phila., I, 1818, p. 424. MILXE 

 EDWARDS, Hist. Nat. Crust., Ill, 1840, p. 134. 



Idotea filiformis WHITE, Hist. Crust. Brit. Museum, 1847, p. 95. 



Erichsonia filiformis HARGER with VERRILL, Report U. S. Commissioner of Fish 

 and Fisheries, 1873, Pt. 1, p. 570 (276); p. 316 (22). HARGER, Proc. U. S. 

 Nat. Mus., II, 1879, p. 160; Eeport U. S. Commissioner of Fish and Fisher- 

 ies, 1880, Pt. 6, pp. 355-356, pi. vn, figs. 38-41. 



Erichsonella filiformis RICHARDSON, American Naturalist, XXXIV, 1900, p. 228: 



Proc. U. S. Nat. Mus., XXIII, 1901, p. 543. 

 2858905 26 



FIG. 447. ERICH- 

 SONELLA ATTEN- 

 UATA. MAXIL- 



LIPED. X 20J. 



