ISOPODS OF NORTH AMERICA. 



465 



IOLELLA EROSTRATA (Richardson). 



lanthe erostrala RICHARDSON, Proc. U. S. Nat. Mus., XXI, 1899, pp. 858-859; 

 Ann. Mag. Nat. Hist. (7), IV, 1899, p. 325; American Naturalist, XXXIV, 

 1900, p. 299. 



Locality. Chichagof Harbor, Attu (the Aleutian Islands), Alaska. 



Head two and a half times broader than long, with prominent 

 antero-lateral angulations. Lateral margins pro- 

 duced, entire. In place of the rostrum, which marks 

 many of the known species of this genus, there is a 

 small median point. The eyes are dorsally situated 

 a short distance from the lateral edges. The first 

 pair of antennas are short, not equal to the width of 

 the head. The second pair are broken in the only 

 specimen. 



The first thoracic segment is produced laterally in 

 two angulations. The second, third, and fourth seg- 

 ments are each produced in two angulations, with a 

 small epimeral lobe in between. The fifth, sixth, 

 and seventh segments have each a large anterior lobe 

 and a small posterior epimeral lobe. 



The terminal segment has two bluntly triangular 

 angulations, one on either side of a bluntly triangular 

 central portion. The uropoda are about as long as the 

 caudal segment, are stj^liform, with branches jiearl\ r 

 equal. The distal extremity of the peduncle and the 

 branch of the first pleopoda of the male are fused and produced at the 

 tip, as in Janiropsis Sars. The first pair of legs are prehensile. The 

 others are simple, bi-unguiculate. One specimen, a male, was collected 

 at Chichagof Harbor, Attu (Aleutian Islands), by Dr. W. H. Dall. 



Type.C&t. No. 22610, U.S.N.M. 



IOLELLA HOLMESI (Richardson). 

 Tole holmesi RICHARDSON, Bull. U. S. Fish Comm., XXIV, 1905, pp. 216-217. 



Localities. Stephens Passage, southeastern Alaska; vicinity of 

 Naha Bay, Behm Canal, southeastern Alaska. 



Depth. 41 to 188 fathoms. 



Body yellow in color, spotted with numerous brown dots. 



Head broader than long, with frontal margin almost straight, very 

 slightly produced in the middle. On either side, a little anterior to the 

 middle of the lateral margin, is a process terminating in two spines. 

 The eyes are large, composite, and placed near the lateral margin, 

 about halfway between the posterior and anterior margins of the 

 head. The first pair of antennae extend to the end of the fourth joint 

 of the peduncle of the second pair. The basal joint of the peduncle 

 2858905 30 



FIG. 520. I O L E L L A 

 EROSTRATA. X 13j. 



