NO. 1175.- ISOPODS OF THE PACIFIC COAST-^ItlCHAIWSON. 



853 



Legs slender, with dactyli biiinguiculate. 



Color of specimen brown. Lateral edges of thoracic segments col- 

 orless. 



Fig. 26.— Eusyjjmerds antennatus. X 8. 



FiQ. 27.— Max- 



ILLIPED O F 

 ECBYMMERUS 

 ANTENNATC8. 



One individual from off Abteojos Point, Lower California, station 

 2835, was collected by the U, S. Fish Commission steamer Albatross; 

 depth, 48 fathoms. 



Type.—^o. 22580, U.S.N.M. 



Family X. ARCTURIDiE. 



28. ARCTURUS Latreille. 



Flagellum of second pair of antennje more than four-jointed. Fourth 

 segment of thorax not greatly longer than others. Marsupium of female 

 composed of four pairs of plates. Posterior thoracic legs biunguiculate. 



ANALYTICAL KEY TO THE SPECIES OF AKCTURUS. ' 



a. End of abdomen notched, as seen from above. 



b. Body smooth and free from spines 61. Arcturun heringanus BeneiUct. 



b'. Hody spiny, 

 c. Head and six segments of thorax each witli a pair of spines on the dorsum. 

 Second and third articles of antenna; without spines. 



62. Arcturui longispinia Benedict, 

 c'. Head and segments of thorax with not less than two pairs of spines to the 

 segment. 

 d. Head with one large median spine on anterior part of head in front of eyes. 



63. Arciurus intermedins, new species. 

 d'. Head with three spines on anterior i)art of head in front of eyes. 



64. ArcluruH murdochi Benedict. 

 a'. End of abdomen without notch 65. Arcturua glaber Benedict. 



' Dr. Benedict's key is used in part for the genus Arcturun. Proc. Biol. Soc. Wash- 

 ington, XII (1898), pp. 42, 43. 



