1154 THE VOYAGE OF H.M.S. CHALLENGER. 



with fewer spines than the inner ramus, which is broad ; the peduncles of the third pair 

 broad, longer than the rami, reaching beyond the telson, having some small marginal and 

 apical spines ; the' rami minute, subequal in length, narrow, and almost acute. 



The Telson rather longer than broad, the sides converging below to a not very acute 

 apex ; there is a small spine near each lateral margin rather above the centre. 



Length. — The specimen, in the position figured, measured, in a straight line from the 

 rostrum to the extremity of the uropods, scarcely a fifth of an inch. 



Locality.— Station 241, North Pacific, June 23, 1875 ; lat. 35° 41' N.; long. 157° 42' 

 E. ; depth, 2300 fathoms; bottom, red clay; bottom temperature, 35°"1. One specimen. 



Remarks. — Beyond the fact of its requiring a new genus for its reception, there is 

 nothing in the character or appearance of the specimen to enhance the probability 

 of its having actually come from so great a depth. That it was thought worthy of 

 exceptional care, or considered to be a specimen of exceptional interest, is implied by its 

 having been mounted during the voyage. 



The specific name, derived from the Greek opyviwv, of the fathoms, refers to the great 

 depth of the ocean at the place where the specimen was obtained. 



Family Coeophiida 



In 1813 Leach instituted the family Corophini for the single genus Corophium, but 

 the following year he merged the Corophini in the larger family Pocloceridse. In 1849 

 Dana established the family Corophidse for the genera Cerapodina, Cerapus, Corophium, 

 Podocerus, Unciola, Atylus, and Clydonia; in 1852 he upheld this family, with the 

 three subfamilies, Clydoninse, Corophinse, Icilinse, assigning to the Clydoninse only 

 Clydonia, to the Icilinse Icilius and Pterygocera, to the Corophinse the genera 

 Corophium, Siphoncecetes, Platophium, Cyrtophium, Unciola, Podocerus, Cratophium, 

 Cerapus, Cerapodina, and Erichthonius. Costa in 1857 divided the family Podo- 

 ceridei into three subfamilies, the Podocerini with the genera Ericthonius, Cerapodina, 

 Cerapus, Podocerus ; the Unciolini with the genera Microdeutopus and Unciola; and 

 the Corofiini with the single genus Corophium. Spence Bate in the same year adopted 

 the family Corophiidse with three subfamilies, the Podocerides containing the genera 

 Pleonexes, Amphitoe, Sunamphitoe, Podocerus, Cyrtophium; the Cerapides with the 

 genera Ericthonius and Siphonocetus; the Corophiides with the genus Corophium. In 

 1859 Bruzelius assigned to the "Corophidse, Dana," the genera Corophium,, Erichtonius, 

 Jassa, Podocerus, Autonoe, Amphithoe. In 1862 Spence Bate accepted the limits of 

 the Corophiidse, which Dana had assigned them in 1852, but he omitted Pterygocera and 

 included the genera Amphithoe, Sunamphitho'e, Dercothoe, Nsenia, Cratippus, Dryope, 



