ISOPODS OF NORTH AMERICA. 373 



Measurements of a female 25 mm. long. 



mm. 



Width of head at the outer margin of eyes 4. 5 



Width of first thoracic segment 6. 5 



Width of second thoracic segment 8 



Width of third and fourth thoracic segments 9 



Width of fifth thoracic segment 8. 5 



Widtli of sixth tlioracic segment 8 



Width of seventh thoracic segment 7. 5 



Lengtli of abdomen 10. 5 



Length of antenna witli flagellum 9 



Measure tnents of a male 28.5 mm. lon<j. 



mm. 



Width of head 5. 5 



Width of first thoracic segment 7. 5 



Widtli of second thoracic segment 8 



^^'idth of third, fourth, fif tli, and sixth thoracic segments 9 



Width of seventli thoracic segment 8. 5 



Length of abdomen 11 



Length of antenna with flagellum 10 



Meatniremenls of a male 35 mm. Inmj. 



mm. 



Width of head G. 5 



Width of first thoracic segment 9 



Widtli of second thorac'ic segment 9. 5 



Width of third, fourth, fifth, and sixth thoracic segments 10. 5 



Width of seventh thoracic segment 10 



Length of abdomen 13 



Length of antenna with flagellum 10 



PENTIDOTEA WHITEI (Stimpson). 



Idotea whitei Stimpsox, Proc. Acad. Nat. Sci. Pliila., 1864, p. 1.55. — Miers, Jour. 

 Linn. Soc. London, XVI, 1883, pp. 42-43. — Richardson, Proc. U. S. Nat. 

 Mus., XXI, 1899, pp. 846-847; Ann. Mag. Nat. Hist. (7), IV, 1899, p. 266; 

 American Naturalist, XXXIV, 1900, p. 227. 



Localities. — Puget Sound ; Monterey Bay, California. From 2IytlhiH. 



Body narrow, elongate, with sides almost parallel; length equal to 

 a little over three times its greatest l)readth, 11 mm.: 34 mm. Length 

 of abdomen a little more than one-third that of entire bod}", 12 

 mm. : 34 nun. 



Head wider than long, with fi-ontal margin ver}' slightly excavate; 

 posterior portion not wider than anterior portion. Eyes moderately 

 large, transversely ovate, compound, and placed close to the lateral mar- 

 gin, about halfway between the anterior and posterior margins. The 

 lirst pair of antenna have four articles; the basal article is twice as 

 broad as any of those following and a little longer; the next two articles 



