MARINE ISOPODA OF NEW ENGLAND, ETC. 



Specimens examined Continued. 



347 



Idotea phosphorea Harger. 



Idotea phosphorea Harger, This Report, part i, p. 569 (275), 1874 ; Proc. U. S 



Nat. Mus., 1879, vol. ii, p. 160, 1879. 

 Verrill, Am. Jour. Sci., Ill, vol. vii, pp. 43, 45, 131, 1874; Proc. Amer. 



Assoc., 1873, pp. 362, 367, 369, 1874; This Report, part i, p. 316 (22), 



1874. 

 WMteaves, Am. Jour. Sci., Ill, vol. vii, p. 218, 1874; Further Deep-sea 



Dredging, Gulf of St. Lawrence, p. 15, "1874." 



PLATE V, FIGS. 27-29. 



This species may be distinguished from the others on this coast 

 by the pointed abdomen or pleon. Young individuals sometimes re- 

 semble the young of J. irrorata, but may still be distinguished by the 

 epimeral sutures of the second and third thoracic segments, which 

 do not entirely cross the segment, but allow more or less of the poste- 

 rior part of the edge of the segment to form a part of the margin of the 

 animal as seen from above. From Synidotea nodulosa it may be distin- 

 guished by the evident epimeral sutures and by the three acute teeth 

 at the base of the pleon on each side, instead of a single obtuse tooth, 

 as in that species. For characters separating it from the other Isopoda 

 of the coast see at the close of the description of the genus. 



The body, especially of the young, is rough and tubercular along the 

 median line and often also laterally. Older specimens are much smoother^ 

 losing their large median tubercles but never becoming as smooth as in the 

 preceding species. The head is narrowed behind. The eyes are of mod- 

 erate size. The flagellum of the antennae (pi. V, fig. 28 a) is shorter than 



