ISOPODS OF NORTH AMERICA. 573 



98. Genus DAJUS Kr0yer.« 



Female with tlii^ head distinct. Middle part of dorsal surface of 

 tliorax distinctly se<;nH'nte(l. 



Abdomen abruptly narrower than the thorax; all six seoments 

 distinct. 



Uropoda present in the form of two simple hunelhe, close together. 



Five pairs of incubator}' plates present. 



Five pairs of legs present, short and thick, and of simihir structure. 



First pair of pleopods well developed, consisting of a paii" of simple 

 large lamella?, placed behind the last pair of incubatory })lates; follow- 

 ing pairs of pleopoda rndinientary. 



iVlale with the segments of the abdomen not distinct. Pleopoda 

 wanting. Uropoda rudimentary, in the form of two small, almost 

 inconspicuous lobes. 



DAJUS MYSIDIS Krciyer. 



Dajus mysidis Kn0YEii, Voy. en Scand. Crust., 1849, pi. xxvni, fig. 1. 



Bopyrus mysidium Packard, Mem. Bost. Soc. Nat. Hist., I, 1887, p. 295, pi. viii, 

 fig. 3. ' 



Lepiophryxus my>iidiis Bi-ciiholz, Zweite Deutsche Nordpolfalirt, 1874, p. 288, ])1. 

 II, fig. 2. 



Dajufi mysidis Lutken, Crustacea of Greenland, 1875, p. 150. — G. 0. Sars, Arch. 

 Math. Nat., II, 1877, p. 354 (254).— Smith iu HARGER,_Proc. U. S. Nat. Mus., 

 II, 1879, p. 158.— Hakcer, Report U. S. Connn. of Fish and Fislieries, 1880, 

 Pt. 6, p. 312. — Hansen, Videnskabelige Meddelelser fra den Naturhistoriske 

 Forening i Ki0benhavn, 1887-88, pp. 197-198. — Sars, Crust, (jf Norway, II, 

 1899, pp. 223-224, pis. xcui, xciv.— Axel Ohlin, Bihang till k. Sv. Vet.- 

 Akad. Handl., XXVI, Afd. iv, No. 12, 1901, p. 39.— RiruAKosox, Proc. 

 U. S. Nat. Mus., XXIII, 1901, p. 579. 



Localities. — Labrador; Greenland; Kingigtok; Duck Island; Murch- 

 ison Sound; Claushavn; latitude 73^ -iS' north, longitude 80^ 3U' 

 west; latitude 72^ 33' north, longitude 71^ 30' west; latitude 71*^ 57' 

 north, longitude 73'^ 56' west; latitude 66° 33' north, longitude 61° 50' 

 west; latitude 64° 56' north, longitude 66° 18' west; west coast of 

 Norway; Kara Sea; Sabine Island; Spitzberg; Jan Mayen; ^Nlurman 

 coast. 



/A7>^/^— Three to 20 fathoms. 



Parasitic on Mysis oculata ((). Fabricius). 



" Body of fully grown female oval ([uadrangular in outline, broadest 

 in front and slightl}" narrowed behind. Cephalon imperfectly defined 

 and curved downward, frontal margin straight. Lateral parts of 

 mesosome greatly swollen and projecting anteriorly in the form of 

 bluntlx' rounded pr<)tub(>rances extending be\'ond the limits of the 

 cephalon, median part subdepressed and exhibiting 5 or 6 distinct 



f'See Sars for characters of genus. Crust, of Norway, II, 1899, p. 222. 



