386 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



Range: Eastern Pacific from Punta Eugenia, Lower California, and 

 from Puerto Refugio, Angel de la Guarda Island, Gulf of California, 

 Mexico, to Caldera, Chile; Clarion Island, Mexico; Cocos Island, 

 Costa Rica; Galapagos Islands, Ecuador. Western Atlantic from Beau- 

 fort, North Carolina, to Desterro, Brazil; Bermudas. Shore to 50 

 fathoms. 



Key to the Pacific American Species of Mkrophrys 



la. Two flattened lobes on the side walls of the carapace, one 



hepatic, one branchial 



2a. Lateral lobes rimmed or collared. Carapace much longer 

 than broad, granules many, two spines in a transverse line 

 at widest part of branchial region. Margin of basal antennal 

 article with an outer lobe platysoma 



2b. Lateral lobes beveled and polished. Carapace little longer 

 than broad, granules few and tufted with hairs, four long 

 spines on each branchial region, three of these in a trans- 

 verse line. Margin of basal antennal article without an 

 outer lobe. 



Peru and Galapagos aculeatus 



lb. No flattened lobes on side walls of carapace, but spines or gran- 

 ules sometimes present 



3a. Two long spines on branchial region near lateral angle. 

 Anterior branchial regions not swollen. Hepatic margin 

 with two short spines. A long spine on the carpus of the 

 first three legs. One tooth or spine on basal antennal seg- 

 ment. 

 Peru and Chile weddelli 



3b. A single spine or lobe at lateral angle, anterior branchial 

 regions greatly swollen. Hepatic margins without two short 

 spines, a cluster of granules sometimes present. Three teeth 

 or spines on basal antennal segment 



4a. Lateral spine sharp and slender, carapace coarsely gran- 

 ulate. Rostral horns, middle antennal spine, and pre- 

 orbital spine elongate. Cheliped of adult male slender, 

 palm not inflated, fingers not widely gaping. Male first 

 pleopod without customary swelling basal to apex 

 branchialis 



