PART 1 GARTH : PACIFIC OXYRHYNCHA 247 



males being absorbed in the greater length of the rostrum of the larger 

 individual. The writer therefore considers it to be of the latter species, 

 rather than E. trifurcatus, which has Cape San Lucas, Lower California, 

 as type locality. 



Eupleurodon rathbunae Garth 



Epialtus peruvianas, Finnegan, 1931, p. 620. (Not E. peruvianas Rath- 

 bun.) 

 Eupleurodon rathbunae Garth, 1939, p. 13, pi. 3, figs. 1-5; 1946, p. 377. 



Type: Female holotype, U.S.N.M. No. 77366. 



Type locality: Gardner Bay, Hood Island, Galapagos Islands, Velero 

 III station 27-33. 



Localities subsequently reported: Known only from the type locality 

 and from Charles Island, Galapagos, St. George Expedition (Finnegan, 

 1931). 



Atlantic analogue: None. A Galapagos endemic species. 



Diagnosis: Female: Rostrum of moderate length, medially sulcate, 

 terminally emarginate. Tips of hepatic lobes narrowed and directed for- 

 ward ; hepatic width exceeding branchial. Orbital margins convex, making 

 an obtuse angle with straight anterolateral margins. Merus of external 

 maxilliped notched to receive palpus. Male unknown. 



Description: Carapace pentagonal, depressed anteriorly and laterally, 

 a bold cardiogastric ridge and a cross ridge at hepatic level. A single pair 

 of tubercles on gastric region, a small tubercle near the posterolateral 

 lobes, and a cardiac tubercle at a slightly posterior level. Lobes and 

 tubercles clavately setose. Hepatic lobes strongly recurved, outer margins 

 forwardly directed, subparallel, tips rounded ; width of carapace at middle 

 of anterior lobes greater than between posterior lobes and greater than 

 distance from tip of anterior lobe to midpoint of posterior margin of 

 carapace. Rostrum more than one-third as long as postfrontal portion of 

 carapace and with an average breadth of one-half its length, lateral mar- 

 gins raised near tip only, extremity faintly bilobed, lobes rounded, a slight 

 median sulcus. 



Merus of outer maxilliped notched at anterointernal angle to receive 

 palpus, first article of palp enlarged and flattened, last two articles small 

 and cylindrical, hidden behind merus. 



Cheliped with visible portion of merus and carpus nodose, merus with 

 a swelling on superior margin at basal third, carpus with a prominent 

 inner node and one or more superior nodules ; propodal finger deflexed, 

 dentate; movable finger with three or four denticles. 



