384 



BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



small tubercles in longitudinal series in the median line at the base 

 of this segment. ' The sides of the abdomen converge gradually to a 

 narrow extremity, which has a deep median excavation. 



SYNIDOTEA MARMORATA (Packard). 



Idotea marmorala PACKARD, Mem. Bost. Soc. Nat. Hist., I, 1867, p. 296, pi. vin, 



fig. 6. WHITEAVES, Canad. Nat., 1875, p. 262. 



Idotea bicuspida STREETS and KINGSLEY, Bull. Essex Inst., IX, 1877, p. 108. 

 Synidotea bicuspida HARGER, Proc. U. S. Nat. Mus., II, 1879, p. 160; Report 

 U. S. Comm. of Fish and Fisheries, Pt. 6, 1880, p. 352. 



Edotea bicuspida MIERS, Jour. Linn. Soc. 



London, XVI, 1883, p. 66. 

 tiynidolea marmorata BENEDICT, Proc. Acad. 

 Nat. Sci. Phila., 1897, p. 392. RICHARD- 

 SON, Proc. U. S. Nat. Mus., XXIII, 1901, 

 p. 542. ORTMANN, Proc. Acad. Nat. Sci. 

 Phila., 1901, p. 156. 



Localities. Labrador; Grand Bank; 

 Battle Harbor, Labrador. 

 Depth. 12 to 129 fathoms. 

 Body ovate, two and three-eighths 

 times longer than broad, 8 mm. : 19 mm. 

 Length of abdomen nearly equal to one- 

 third the entire length of the body, 

 6 mm. : 19 mm. 



Head with a deep median excavation 

 or notch. On either side of the median 

 notch the front is produced anteriorly 

 and has the lateral portion bend down- 

 ward, forming an angle with the dorsal portion. The eyes are large 

 and round, composite in structure, and placed about the middle of the 

 head at the extreme lateral margins. The first pair of 

 antennas have the basal articles long, not expanded, and 

 about equal in length to the second article; the third is 

 a little longer than the second; the fourth is about as 

 long as the second. The first antennas extend a little 

 beyond the third article of the peduncle of the second 

 pair of antennas. The basal article of the second antennae 

 is short, and almost inconspicuous from a dorsal view; 

 the second article is also short; the third is twice as long 

 as the second; the fourth is one and a half times longer 

 than the third; the fifth is one and a half times longer 

 than the fourth. The flagellum consists of fourteen 

 articles. When retracted, the second antennas extend to 

 the middle of the fourth thoracic segment. The maxilliped has a 

 palp of three articles. 

 The four anterior segments of the thorax are longer than the last 



FIG. 422. SYNIDOTEA MARMORATA 

 (AFTER BENEDICT), x 2. 



FIG. 423. SYNJ- 

 DOTKA MAKMO- 

 RATA. MAXIL- 

 LIPED. x 201. 



