348 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



MESIDOTEA'ENTOMON (Linnaeus). 



Oniscus entomon LINNMU-S, Syst. Nat., 12th ed., I, Pt. 2, 1767, p. 1060. PALLAS, 



Spicil. Zool., IX, 1772, p. 64, pi. v, figs. 1-6. 

 Squilla entomon DE GEEK, Mem. pour servir a 1'Hist. des Insectes, VII, 1778, p. 



514, pi. xxxn, figs. 1-10. 



Asellua entomon OLIVIER, Encycl. M6th., IV, 1789, p. 253. 

 (?) Cymothoa entomon FABRICIUS, Ent. Syst., II, 1798, p. 505. 

 Idotea entomon Bosc, Hist. Nat. des Crust., II, 1802, p. 178. LATREILLE, Hist. 



Nat-. Crust, etlns., VI, 1803-4, p. 361; VII, pi. LVIII, figs. 2-3. (?) LAMARCK, 



Hist, des Anim. sans Vert., 1st ed.,V, 1818, p. 159. RATHKE, Neuste Schriften 



der naturf. Gesellsch. in Danzig, I, 1820, p. 109, pi. iv. (?) DESMAREST, 



Consid. Crust., 1825, p. 289. KR0YER, Vid. Selsk. Skrift., VII, 1838, p. 



323. MILNE EDWARDS, Hist. Nat. Crust., Ill, 1840, p. 128. KR0YER, Nat. 



Tidsskr., II, 1846-49, p. 402. WHITE, List Cr. Brit. Mus., 1847, p. 93. 



BRANDT, Crust, in Middendorf s Sibirische Reise, II, 1851, p. 145. 

 (?) Saduria entomon ADAMS in WHITE, Sutherland's Voy. Baffin's Bay, Appendix, 



1852, p. 207. 



Idotitga longicauda LOCKINGTON, Proc. Cal. Acad. Sci., VII, 1877, Pt. 1, p. 45. 

 Idotea entomon MEINERT, Nat. Tidsakr. (3), XI, 1877, p. 84. BRANDT, Comptes 



Rendus, 1880, p. 713; Ann. Mag. Nat. Hist., VI, 1880, p. 98. 

 Glyptonofus entomon MIERS, Trans. Linn. Soc. London, XVI, 1883, pp. 12-13, pi. 



i, figs. 1-2. (See Miers for further synonymy.) RICHARDSON, Proc. U. S. 



Nat. Mus., XXI, 1899, p. 843; Ann. Mag. Nat. Hist. (7), IV, 1899, p. 262. 



Localities. Circum polar; west coast of North America to. Pacific 

 Grove, California; Stockholm's skargard (J. Lindahl); Kielerbucht, 

 Germany; Nakvak, Labrador; Kara Sea. 



Found on beach; 5-8 fathoms in sand and gravel; 15 fathoms. 



Body ovate, broad anteriorly, and tapering to a narrow pointed 

 extremity; about two and a half times longer than broad, 7 mm. : 17 

 mm. Length of abdomen nearly equal to half the length of entire 

 body, 8 mm. : 17 mm. 



Lateral margins of head cleft, with the two lobes about equal in 

 size, the anterior one more rounded in outline, the posterior one more 

 acute; the posterior lobe is not produced at the sides beyond the ante- 

 rior one. The front of the head is deeply excavate between the antero- 

 lateral lobes, and there is a small median excavation. The eyes are 

 distinct, small and round, compound in structure, dorsally placed at 

 the base of the lateral cleft. The first antennae have the basal article 

 enlarged, about twice as wide as the second article and very little 

 longer; the third article is one and a half times longer than the second; 

 the fourth article is just a little longer than the third. The first antennae 

 extend to the middle of the fourth article of the peduncle of the second 

 pair of antenna?. The basal article of the second antennae is almost 

 inconspicuous; the second, tnird, and fourth articles are all short, about 

 equal in length, although the second is nearly twice as wide as the two 



"The description is from a small specimen. In the adult the flagellum consists of 

 more joints. 



