70 ME. E. J. MIEES OK THE IDOTEID^. 



decidedly narrower-oval form ; tlie antero -lateral angles of the 

 head are perhaps not so prominent and more rounded; the eyes 

 are smaller. Length of the largest example about 1 inch 1 line 

 (28 millim.) ; breadth about f-^ inch (10 millim.). In this speci- 

 men the flagellum of the antennae is about 30-jointed, but in the 

 smaller example (length f inch, 21 millim.) only about 21-jointed. 



§§ AntenncB very small, with the jlagellum rudimentary ; fost- 

 abdomen uniarticulate. (•^^dotia.^----- C^'^ 



The species of this section may be distinguished by the follow- 

 ing characters : — 

 a. Dorsal surface of the lody without a median line of tubercles. 



Lateral margins of the thoracic segments nearly straight and 

 even ; postero-lateral angles of the three posterior thoracic seg- 

 ments rounded ; lateral teeth near the base of the postabdomen 

 obsolete, 1. -E^- trilola (Say). 



Lateral margins of the thoracic segments somewhat produced 

 and angulated; postero-lateral angles of the three posterior 

 segments rounded ; subbasal lateral teeth of the postabdomen 

 usually distinct. 2. E. montosa (Stimpson). 



Lateral margins of the thoracic segments straight ; postero- 

 lateral angles of the three posterior segments acute ; subbasal 

 lateral teeth of the postabdomen distinct. 



3. JS. magellanica (Cunningham). 



b. Dorsal surface of the body with a median line of tubercles. 



Lateral margins of the thoracic segments nearly straight ; 

 postero-lateral angles of the three posterior segments subacute ; 

 subbasal lateral postabdominal teeth obsolete. 



4. E. tuberculata, Guerin. 

 Edotta teiloba. 



Idotea triloba, Say, Journ. Acad. Nat. Sci. Philad. i. p. 425 (1818); 

 M.-Edw. Hist. Nat. Cr. iii. p. 134 (1840); BeKay, Zool. of New 

 York Fauna, Cr. p. 43 (1844); Leidy, Journ. Ac. Nat. Sci. Philad. 

 (ser. 2) iii. p. 150 (1855). 



Jara? triloba, E'hite, List Crust. Brit. Mus. p. 97 (1847). 



Epelys trilobus, Smith, Rep. U.S. Fish Comm. pt. i. p. 571, pi. vi. 

 fig. 28 (1874); Verrill, Amer. Journ. of Sci. and Arts, (ser. 3) vii. 

 p. 135 (1874) ; id. Proc. Amer. Assoc, p. 372 (1874) ; id. Rep. U.S. Fish 

 Comm. pt. i. p. 370 (1874); Harger, Pr. U.S. Nat. Mus. ii. p. 160 

 (1879) ; id. Rep. U.S. Fish Comm. pt. vi. Isopoda, p. 358, pi. vii. figs. 

 42, 43 (1870). 



