No. 5. — Reports on the Dredging Operations off the West Coast 

 of Central America to the Galapagos, to the West Coast of 

 Mexico, and in the Gulf of California, in charge of Alexander 

 Agassiz, carried on hy the U. S. Fish Commission Steamer 

 "Albatross," during 1891, Lieut-Commander Z. L. Tanner, 

 U. S. N., Commanding. 



[Published by permission of Marshall McDonald and J. J. Brice, 

 U. S. Fish Commissioners.] 



XXII. 

 The Isopoda. By H. J. Hansen. 



The collection contains in all fifteen species, fourteen of which, all 

 marine, I have considered new to science, while one form — belong- 

 ing to the Oniscidse — is terrestrial in habit, and proves to be a well 

 known species. Of the fourteen marine species, eight are free-living 

 forms, and one is parasitic on fishes ; these nine species are easily 

 referred to genera established many years ago. The remaining five 

 species belong to the subfamily Bopyrinse, of the very extensive family 

 Epicaridea ; they present several peculiarities in structure, and more- 

 over they are rather interesting since no form of the Bopyrinne has 

 heretofore been found on truly deep-sea animals. For particulars, how- 

 ever, the reader must be referred to the special description later on. 



Besides my special account a few remarks must suffice.-^ Since each 



1 The Director of the Entomological Department of the Zoological Museum in 

 Copenhagen, Inspector Dr. F. Meinert, had commenced to deal with the material, 

 but being engaged in other work, he transferred to me the preparation of this 

 report. Only the following particulars are of interest. He had recognized the 

 two species of Asellota and all the species of Cymothoidae as new to science; 

 furthermore, he had furnished them with names, and on the labels briefly men- 

 tioned the species already published to which each of the new forms was most 

 closely allied. Some of the names and most of these hints on affinity are adopted 

 in the report, which otherwise is wholly a work of my own. Yet it must finally 

 be mentioned that Mr. G. Budde-Lund has determined the single species of 

 Oniscidae. 



VOL. XXXI. — KG. 5. 



