500 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



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

 thoracic segments and epimera defined only on the shorter side. 



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

 ment is small and narrow, bifid at the tip. 



Palp of the maxillipeds wanting. 



Incubatory plates of the longer side large and well developed and 

 concealing the entire incubatory pouch; those of the shorter side very 

 small. 



Legs of the larger side of the body 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 body 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 (Kr^yer). 



Bopyrus abdominalis KR0YER, Nat. Tidsskr., Ill, 1840-1841, pp. 102-112, 289-299, 

 pis. i, it ; Kongelige Danske Videnskabenes Selskabs naturvidenskabelige 

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



Phryxas hippolytes RATHKE, Nova Afta Academiae Casariae Leopoldino-Carolinse 

 Naturae Curiosorum, 1843, p. 40, pi. n, figs. 1-10. 



Bopyrus abdominalis KR0YER, Voy. en Scand., Crust., 1849, pi. xxix, fig. 1. 



Phryxus abdominalis LILLJEBORG, GEfvers. Kongl. Vet. Akad. Forh., IX, 1852, 

 p. 11. STEENSTRUP and LUTKEN, Vidensk. Meddelelser, 1861, p. 275 (9) 

 1862. BATE and WESTWOOD, Brit. Sessil-eyed Crust., II, 1868, p, 234. 

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

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

 SMITH in HARGER, Proc. U. 8. Nat. Mus., II,' 1879, p. 158. HARGER, Rep. 

 U. S. Fish Comm., 1880, Pt. 6, p. 312. HANSEN, Videnskabelige Med- 

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

 AXEL OHLIN, Akademisfc Afhandling, XXII, 1895, pp. 18-19; Bihang till 

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

 BARS, Crust, of Norway, II, 1899, pp. 215-217. pis. xo, xci. RICHARDSON, 

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

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



Localities. Circumpolar in distribution. 



Atlantic coast localities: Massachusetts Bay, on Pandalus borealis, 

 Spiron.tocaris spinus, S. liljeborgii, and Pandalus montagui; Cashes 

 Ledge, Gulf of Maine, on Pandalm borealis and S. pusiola; Georges 

 Bank on Pandalus leptocerus; Halifax, Nova Scotia, on S. pusiola, 

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

 S. gaimardii and S. gibba; Cape Cod on P. montagui, P. leptocerus, 

 S. liljeborgii, /S. pmiola, and S. polar ix; Grinnell Land, Discovery 

 Bay, Greenland, Cape Dudley Digges on S. phippsii and .V. polaris; 

 Inglefield Gulf on S. polaris; latitude 73 48' north, longitude 80 30' 

 west, on S. polaris; latitude 64 56' north, longitude 66 18' west, on 

 S. phippsii; off Marthas Vineyard, on Pandalus leptocerus and 8. lilje- 



