264 



Miss H. Richardson on the Isopods of the 



Fiff. 20. 



Hah. Straits Juan de Fuca, opposite Fort Townsend, Van- 

 couver Island ; Gulf of Georgia, Orcas Island ; Pacific Grove, 

 San Pedro, and Monterey Bay, California. 



38. Idotea gracilUma^ Dana. 



Idotea gracillima, Dana, Proc. Acad. Nat. Sci. Philad. vii. 1854, p. 175 ; 

 Stimpson, Bost. Journ. Nat. Hist. vi. 1857, p. 505 ; Miers, Journ. 

 Linn. Soc. London, Zool. xvi. 1883, p. 35. 



Hah. California. 



39. Idotea urotoma, Stimpson. 



Idotea urotoma, Stimpson, Proc. Acad. Nat. Sci. Philad. 1864, p. 155; 

 Miers, Journ. Linn. Soc. London, Zool. xvi. 1883, p. 34. 



Hah. Puget Sound. 



40. Idotea j'ectih'neata, Lockington. 



Idotea rectilmeaia, Lockington, Proc. Cal. Acad. Sci. vii. 1877, pt. 1, 

 p. 36 ; Miers, Journ. Linn. Soc. London, Zool. xvi. 1883, p. 34. 



Hah. Along the Pacific coast from Humboldt County, 

 California, to Ensenada, Lower California. 



From an examination of speci- 

 mens, this species, which Miers * 

 says is scarcely to be distin- 

 guished from /. ochotensis, 

 Brandt, is seen to be specifically 

 distinct. It differs from /. ochot- 

 ensis in the proportions of the 

 body, /. rectilineata being more 

 slender — about five times as long 

 as broad — while in I. ochotensis 

 the length is only three and a 

 half times greater than the 

 width ; in the relative length of 

 the antenna? to the body and the 

 proportions of the joints in the 

 peduncle of the antennte, the 

 antcnnai in /. ochotensis reaching 

 only to the posterior margin of 

 the third thoracic segment (in all 

 the specimens examined), the 

 joints of the peduncle being 

 short and stout, while in /. recti- 

 lineata the antennai extend to the posterior margin of the 

 fifth thoracic segment, the joints of the peduncle being long 

 and slender ; in the form ot the anterior margin of the liead, 



* Journ. Linn. Soc. London, Zool. xvi. 1883, p. 34. 



Idotea rectilhieata, Lockington. 

 X 2. 



