. Bulletin - United States National Museum. Science. ISOPODS OF NORTH AMERICA. 329 from the segments, are eoiispicuous from a dorsal view, and are pro- duced at the sides in processes which are rather bknit at their extremities. The first two seo-nieiits of the abdomen are short. The t(M-niinal segment is long and pi'oduced to an extremit}'^ which has a V-shaped excavation. The length of the terminal segment is a little less than one- fourth that of the entire bod}', being 8 mm. long. Near the bas(^ is a transverse depression marked on either side by a blunt expansion of the lateral margin, pr
. Bulletin - United States National Museum. Science. ISOPODS OF NORTH AMERICA. 329 from the segments, are eoiispicuous from a dorsal view, and are pro- duced at the sides in processes which are rather bknit at their extremities. The first two seo-nieiits of the abdomen are short. The t(M-niinal segment is long and pi'oduced to an extremit}'^ which has a V-shaped excavation. The length of the terminal segment is a little less than one- fourth that of the entire bod}', being 8 mm. long. Near the bas(^ is a transverse depression marked on either side by a blunt expansion of the lateral margin, probably indicative of a coalesced segment. The first four pairs of legs are slender, directed forward, and densely covered with long, slender hairs on the inferior margins of all the articles. The first pair of legs is shorter than the three following pairs. The last three pairs of legs are ambulatory. ARCTURUS LONGISPINUS Benedict. Arcturus longispinus Benedict, Proc. Biol. Soc. Washington, XII, 1898, pp. 44- 45.—Richardson, Proc. U. S. Nat. Mus., XXI, 1899, ]>. 854; Ann. Mag. Nat. Hist. (7), IV, 1899, p. 275; American Naturalist, XXXIV, 1900, p. 229. Locality.—Aleutian Islands. Dej>th.—55 fathoms. Body narrow, elongate, nearly five times longer than wide, 7 mm.: 85 nun. Head wider than long, 7 mm. : 4 mm., with the anterior margin deepl}' excavate l)etween the produced antero-lateral angles. The eyes are small, round, composite, and situated at the sides of the head halfway between the antero-lateral angles and the posterior margin. There are two extremely long spines, 7 mm. in length, situated about the middle of the head between the eyes, one on either side of the median line. The first pair of antenna have the basal article long and somewhat dilated, about twice as long as wide; the sec- ond and third articles are subequal in length, each being half as wide as the basal article and much shorter; the fourth article is about one and a half times longer than tlie t
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