350 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



The segments of the thorax arc subequal, the first and the last being 

 a little shorter than any of the intermediate ones. The epimera are dis- 

 tinct on all the segments, from the second to the seventh, inclusive, 

 and occupy the entire lateral margin. Those of the last five segments 



are greatly produced pos- 

 teriorly in extremely long, 

 acutely pointed processes. 



FIG. 375. MESIDOTEA ENTOMON (AFTER MIERS). a, HEAD FIG. 376. MESIDOTEA 



WITH BOTH ANTENNAE. X J. b, OPERCULAR VALVE (IN- ENTOMON. MAXIL- 



NER SIDE). X f. LIPED. X 20J. 



increasing in length to the sixth segment; the epimeron of the seventh 

 segment is only about half as long as that of the sixth. 



The first three pairs of legs are subchelate, with propodus dilated, 

 and dactylus reflexed. The inferior margin of the propodus is armed 

 with long and short spines. The last four pairs of legs are ambulatory. 



The abdomen is composed of five segments, four short ones, followed 

 by a long terminal segment, parti} 7 coalesced with the last short seg- 

 ment. The sides of the terminal segment converge to a narrow pointed 

 extremity, with indications of lateral angles about two-thirds the dis- 

 tance from the base to the extremity of the segment. The opercular 

 valves are in two parts, a large upper portion and a very small ter- 

 minal portion. Within the valves on the underside is a small lobe 

 attached to the terminal division and representing the inner branch of 

 the modified uropoda. 



MESIDOTEA SABINI (Kr^yer.) 



Idotea sabini KR0YER, Nat. Tidsskr. (2), II, 1846-49, p. 401. REINHARDT, Natur. 

 Bidrag til en Beskrivelse af Gronland, 1857, p. 34. LUTKEN, List of Crust, 

 of Greenland in Arctic Manual, 1875, p. 149. SARS, Arch. f. Math, og 

 Naturvidensk., II, 1877, p. 350. 



Glyptonotus sabini MIERS, Jour. Linn. Soc. London. XVI, 1883, pp. 15-17, pi. i, 

 figs. 3-5. HANSEN, Videnskabelige Meddelelser fra den naturhistoriske 

 Forening i Kj0benhaven, 1887-88, p. 187. AXEL OHLIN, Akademisk Afhan- 

 ding, XXII, 1895, pp. 13-14. RICHARDSON, Proc. U. S. Nat. Mus., XXI, 

 1899, p. 844; Ann. Mag. Nat, Hist. (7), IV, 1899, p. 263. 



Chir Idotea sabini STEERING, Ann. Mag. Nat. Hist. (7), V, 1900, p. 14. RICHARD- 

 SOX, American Naturalist, XXXIV, 1900, p. 226; Proc. U. S. Nat. Mus., 

 XXIII, 1901, p. 538. 



