ISOPODS OF NORTH AMERICA. 587 



The first two abdominal segments have their lateral margins covered 

 by the seventh thoracic segment. The three following segments com- 

 plete the elliptical outline of the body, their lateral margins forming a 

 line curving inward toward the terminal segment. The last abdomi- 

 nal segment is quadrangular in outline, its post-lateral angles rounded, 

 and extends a little distance beyond the epimera of the preceding seg- 

 ment. The uropoda are transformed into opercular valves. At the 

 posterior end of each large lamellar valve is a small setose joint. The 

 third, fourth, and fifth abdominal segments have plates on the ventral 

 side extending from the margin inward in the form of lamellae, those 

 of the fifth segment being longest and largest, but not meeting in the 

 median line, being a little distance apart. 



The legs are simple, ambulatory. 



Three specimens were collected by Mr. J. M. Jones at the Bermudas, 

 and about twenty more by Prof. A. E. Verrill and part} 7 at the same 

 locality in 1898. Others were collected in 1901 at Long Bird Island, 

 Bermudas. 



Family XXIV. EUBELID^. 



Flagellum of the second antenna? generally more or less obscurely 

 triarticulate, rarely only biarticulate; peduncle with the first article 

 very short, the third article always shorter than the second, the fourth 

 article a little longer than the second, the fifth article always the longest. 



Eyes distinct, composed of numerous ocelli. 



Head with the epistome forming a continuous frontal marginal line, 

 often effaced in the middle. The antennal foramina are moderately 

 large, the antennal tubercles small, often wanting. Clypeus short, 

 vaulted, lobate at the sides. The pleurae of the head are fused; the 

 vertical marginal line does not reach the frontal margin; there is no 

 vertical inframarginal line. 



The inner lobe of the first or inner maxillae has numerous plumose 

 processes (5-15); the outer or second maxillae are wide, obscurely 

 bifid, the exterior lobe much wider and larger than the inner. 



The first segment of the thorax has thick epimera, separated from 

 the middle of the segment by a sutural furrow, the lateral margin pos- 

 teriorly cleft, rarely entire. The anterior articulating part of all the 

 segments (2-7) manifestly separated from the posterior part. The 

 marsupium is present. 



The terminal abdominal segment is triangularly or even quadran- 

 gularly produced, not extending or extending very little beyond the 

 epimera of the preceding segment. The outer branch of the first or 

 generally of all the pleopoda furnished with tracheae. Uropoda short, 

 not extending or extending very little beyond the terminal segment of 

 the abdomen. Peduncle large, wide. Outer branch small or minute. 



a See Budde-Lund for characters of family, A revision of Crustacea Isopoda Ter- 

 restria, 1899, Pt. 1, Eubelum, pp. 2-3. 



