500 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



Segments of thorax distinct on tlie dorsal surface. Lateral parts of 

 thoracic segments and epimera delined only on the shorter side. 



Abdomen consists of live segments only; the fifth or terminal seg- 

 ment is small and narrow, bitid at the tip. 



Palp of the maxillipeds wanting. 



Incubator}' plates of the longer side large and well developed and 

 concealing the entire incubatory- pouch; those of the shorter side ver}- 

 small. 



Legs of the larger side of the );)ody all wanting, with the exception 

 of the first one. 



There are four pairs of single-branched pleopoda, the lamella' of the 

 longer side of the })ody being larger than those of the opposite side. 



Male with all the segments of the thorax distinct; those of the abdo- 

 men fused, though more or less indicated at the sides, on the lateral 

 margins. Uropoda wanting. Pleopoda wanting. 



PHRYXUS ABDOMINALIS (Kr0yer). 



Bopiirm ahdommalis Kr0YER, Nat. Tidsskr., Ill, 1840-1841, pp. 102-112, 289-299, 

 pis. I, II ; Kongelige Danske Videnskabenes Selskabs naturvidenskabelige 

 og mathematiske Afhaudlinger, IX, 1842, p. 263. 



PJiryxKs hipjiohjtes Rathke, Nova Acta Academice Ca-sarife Leopoldino-Caroliiife 

 Natune Curiosorum, 1843, p. 40, pi. ii, figs. 1-10. 



Bopyrus abdominalis Kr0yer, Yoy. en Scand., Crust., 1849, pi. xxix, tig. 1. 



Phryxus abdominalis 'LiJjLjeborg, (Eixers. Kongl. Vet. Akad. Forh., IX, 18.52, 

 p. 11. — Steenstrup and Lutkex, Vidensk. Meddelelser, 1861, p. 275 (9) 

 1862.— Bate and We«t\vood, Brit. Sessil-eyed Crust., II, 1868, p. 234.— 

 Norman, Rep. Brit. Assoc, 1869, p. 288; Proc. Royal Soc. Lond., XXV, 

 1876, p. 209.— MiERs, Ann. Mag. Nat. Hist. (4), XIX, 1877, p. 65 (15).— 

 Smith in Harger, Proc. U. S. Nat. Mus., II, 1879, p. 158. — Harger, Rep. 

 U. S. Fish Comni., 1880, Pt. 6, p. 312.— Hansen, Videiiskabelige Med- 

 delelser fra den naturhistoriske Forening i Kj0benhavn, 1887-88, p. 196. — 

 Axel Ohlin, Akademisk Aflmndling, XXII, 1895, pp. 18-19; Bihang till 

 K. Svenska Vet. -Akad. Ilaiidl., XXVI, Afd. iv. No. 12, 1901, pp. 38-39.— 

 Sars, Crust, of Norway, II, 1899, pp. 215-217. pis. xv, xci. — Richardson, 

 Proc. U. S. Nat. Mus., XXIII, 1901, p. 577; XXVII, 1904, pp. 58-59; Bull. 

 U. S. Fish Conuu., XXIV, 1905, p. 220. 



Localities. — Circumpolar in distril)uti()n. 



Atlantic coast localities: Massachusetts Bay, on lunula! us h(/rc(f/i)^, 

 Spirontocaris spinus, A", liijchorgii, and Pandaliix monttujui ; Cashes 

 Ledge, Gulf of Maine, on Pandalus. horealif< and S. jxisiola; Georges 

 Bank on Panddlm leptocerus; Halifax, Nova Scotia, on S. imxiola. 

 S. spinus, and aS. liljehorgii; northeastern part of Grand Bank on 

 S. gaimardii and S. gihha; Cape Cod on P. nioittagui^ I\ leptocenis, 

 8. liljehorgii, S. pusiola, and S. jjolaris; (irinncU Land, Discovery 

 Bay, (Greenland, Cape Dudley Digges on S. j>kip/)sii and S. poIaris; 

 Inglefield Gulf on S. polarix; latitude 73- 48' north, longitude SC^ 30' 

 west, on S. polaris; latitude 04 56' north, longitude i><6- 18' west, on 

 8. phippsii; off Marthas Vineyard, on J\mdahis leptocerm and 6'. lilje- 



