MARINE ISOPODA OF NEW ENGLAND, ETC. 321 



being then small, elongate, oval, and lying near the under surface of 

 the thoracic segments. 



Janira alta Harger (Stimpson). 



Asellodes alta Stimpson, Mar. Inv. G. Manan, p. 41, pi. in, fig. 30, 1853. 



Verrill, Am. Jour. Sci., Ill, vol. vi, p. 439, 1873 ; vol. vii, pp. 411, 502, 



1874; Proc. Amer. Assoc., 1873, p. 350, 1874. 

 Janira alta Harger, Proc. U. S. Nat. Mus., 1879, vol. ii, p. 158, 1879. 



PLATES II AKD III, FIGS. 9, 12, AND 13. 



This species may be at once distinguished from the following by the 

 absence of spines in the dorsal and lateral thoracic regions, from all the 

 other known Isopoda of the coast, by the flattened, scutiform and consoli- 

 dated pleon, bearing well-developed, exerted, biramous uropods, which 

 are, however, fragile. It is more slender than the following species. 



The body is elongated oval in outline, nearly three times as long as 

 broad. The head is produced in front into a prominent but short, acute, 

 median spine or rostrum, and the antero-lateral angles are also acutely 

 produced, but are shorter and less acute than the rostrum. The eyes are 

 prominent and black, situated on the upper surface of the head, near the 

 lateral margins. They are elliptical in outline, with the long axes con- 

 verging toward a point near to, or beyond, the tip of the rostrum. The 

 basal segment of the antennulae is shorter than the rostrum ; the flagellum 

 consists of about thirty segments and does not attain the tip of the fourth 

 antennal segment. The scale on the second segment of the antennas is 

 short and triangular, does not surpass the following segment, and is 

 tipped with a few slender setse. The maxillipeds (pi. Ill, fig. 12 a) have 

 the external lamella (I) obtusely pointed at the apex and angulated on 

 the outer side, otherwise they resemble the same organs in J. spinosa, 

 as do the outer maxillae, the inner maxillae, and the mandibles (pi. Ill, 

 fig. 12 &). 



The thoracic segments are but little broader than the head, the first 

 three and the last two segments are about equal to each other in length; 

 the fourth and the fifth are somewhat shorter. The lateral margins of 

 the segments do not cover the epimera from above, and none of them 

 are produced at the sides into acute and salient angulations, as in the 

 next species. In the first segment the lateral margins are rounded and 

 the epimera project as an angular tooth on each side in front. In the 

 second, third, and fourth segments the emargination is behind a promi- 

 nent but narrow lobe at the anterior angle of the segment and the epi- 

 mera are two-lobed. In the fourth segment the posterior angle is nearly 

 included in the emargination, and in the last three segments the posterior 

 angle is elided and the epimera occupy its place. The legs are elon- 

 gated and armed with spines, especially on the carpal segments. 



The pleon is rounded-hexagonal in outline, minutely and sharply 

 serrate at the sides behind the middle, and undulated over the bases of 

 21 F 



