NO. 1222. ISOPODS OF THE ATLANTIC COAST— RICHARDSON. 501 



?/. Eyes present. 



r. Gnathopods in male imperfectly chelate, without any fin<^er, or with finger 



very short and immovable 5. Heterotanais. 



cf. (Tnathopods in male with chelte fully developed. 



d. Gnathopods in male sometimes very much elongated, with carpus atten- 

 uated, hand very large, oblong, finger elongate and curved, inim()val)le, 

 strongly tuberculate within. Thoracic appendages not specialized into an 

 anterior and a posterior series. Marsupium of female formed of eight 



large lamelhc from the first four free segments 6. Leidoclielia. 



(V. Gnathopods in male with chelfe very stout, the distal section of the penul- 

 timate joint extremely broad, with a toothed margin. Thoracic append- 

 ages specialized into an anterior and a posterior series. Marsupium of 

 female of the normal structure 7. Neotanais. 



1. TANAIS Auclouin and Milne-Ed^A^ards. 



ANALYTICAL KEY TO THE SPECIES OF TANAIS. 



a. Abdomen composed of six distinct segments. Sixtti segment terminated posteri- 

 orly by a blunt median projection. Without transverse setiferous bands crossing 

 first and second abdominal segments. Body robust and tapering. Uropoda 

 four jointed 1. Taii(u>f rohustus Moore. 



a\ Abdomen composed of five segments. Sixth segment without l)lunt median 

 projection, rounded. With transverse setiferous bands crossing first and sec- 

 ond abdominal segments. Body slender, elongated. Uropoda three jointed. 



2. Tanais cavolinii Milne-Edwards. 



I. TANAIS ROBUSTUS Moore. 

 Taiiaiii robustus Moore, Proc. Acad. Nat. Sci. Phila., 1894, p. 90. 

 Ilahltat. — New Jersey . 



2. TANAIS CAVOLINII Milne-Edwards. 



Tanais cavolinii. Milne-Edwakds, in Audouin and INlilne-Edwards, Precis 

 d'Entomologie, I, 1828, pi. xxix, fig. 1; Hist. Nat. des Crust., Ill, 1840, 

 p. 141, pi. XXXI, fig. 6. 



Tanais tomentosus Kr0YER, Naturhist. Tidssk., IV, 1842, p. 183; (2) II, 1847, p. 

 412; Voy. en Scand., Crust., 1849, pi. xxvii, figs. 2 a-q.— Lill.jeborg, Ofvers. 

 Vet. Akad. Forh., Arg., VIII, 1851, p. 23; Meinert, Crust. Isop. Amph. Dec. 

 Danife, 1877, p. 86. 



Crossunis vittatus Rathke, Fauna Norwegens, 1843, p. 39, pi. i, figs. 1-7. 



Tanais ]tirtic<ii((liitus Bate, Rep. Brit. Assoc, 1860, p. 224, 1861. 



Tanais vittatus Lilljeborg, Bidrag Kiinn. Crust. Tanaid., 1865, p. 29. — Bate and 

 Westwood, Brit. Sess. Crust., II., 1866, p. 125.— Stebbing, Trans. Devon. 

 Assoc, 1874, p. 7; 1879, p. 6; Ann. Mag. Nat. Hist. (4), XVII, 1876, p. 78.— 

 Verrill, Am. Jour. Sci., X, 1875, p. 38.— Harger, Proc. U. S. Nat. Mus., 

 II, 1879, p. 162; Report IT. S. Fish Com., 1880, Pt. 6, pp. 418, 419, pi. xiii, 

 figs. 81-82. 



Tanais tomentosus G. O. Sars, Crust, of Norway, II, Pt. 1, 1896, p. 12, pi. v. 



Tanais cavolinii Dollfls, Bull. Soc Zool. de France, XXI, 1897, p. 207; Mem. 

 de la Soc. Zool. de France, XI, 1898, p. 35.— Nor.\ian, Ann. Mag. Nat. Hist., 

 (7) II, 1899, pp. 332,333. (See Norman for synonymy. ) 



ZTaJ^Va?!.— Noank, Connecticut; Long- Island Sound; Greenland; 

 also west coast of Norway ; British Isles ; West France ; Azores ; 

 Mediterranean. 



