20 ALLAN HANCOCK ATLANTIC EXPEDITION REPORT 



Challenger (Henderson); A. Heilprin (Heilprin) ; Plankton-Exped. 

 Humboldt-Stiftung (Ortmann, 1893); New York Univ. Exped. 

 (Rankin, 1900). Bahamas: (Ortmann, 1897); Salt Cay: Northrop 

 (Rankin, 1898). Cuba: (Guerin) ; J. Gundlach (Martens); Cape 

 Cruz, 3 fms: Ara (Boone). Jamaica: (Benedict, 1892) ; J. E. Duerden 

 (Rathbun, 1899). Puerto Rico, San Juan: J. Gundlach (Gundlach); 

 San Juan and Bahia Boqueron: Fish Hawk (Benedict, 1901); Ense- 

 nada, between Ensenada and Guanica, Guanica Harbor, S of Islas Cana 

 Gorda, and Guayanilla Playa: Sci. Surv. Porto Rico and Virgin Ids. 

 (Schmitt, 1935). St. Thomas: A. H. Riise (Stimpson, 1859). Panama: 

 ? Sternbergh and Rowell (Stimpson, 1859); Aspinwall [= Colon]: 

 Rowell (Stimpson, 1859) ; Colon: (Verrill, 1908b). Curagao: J. Boeke 

 (Rathbun, 1920). Brazil, Mamanguape, Rio Goyanna, and Maceio: 

 A. W. Greeley (Rathbun, 1900); Bahia: (Ortmann, 1897); Rio de 

 Janeiro: Novara (Heller, 1862) ; States of Bahia, Rio de Janeiro and 

 Santa Catharina: (Moreira, 1901). 



Material examined. — 

 All 1-49. Punta Rassa near San Carlos Bay, opposite Sanibel Island, 



Florida; May 15, 1949; shore; coll. L. O. Miles. Id', 2? (1 



ov). 

 A145-49. Marco Island near channel S of Big Marco Pass, Florida; 



June 14, 1949; coll. L. O. Miles. 5 d', l?ov. 

 Marco Island, Florida: Sept 15, 1950; shore; coll. L. O. Miles. 4d, 



4? (2 ov). Taken off "finger sponge" in lagoon. 

 N end of Marco Island, Florida; Sept 16, 1950; shore; coll. L. O. 



Miles. 76^,6? (2ov). 

 Lower Matecumbe Key, Florida; Sept 23, 1950; coll. L. O. Miles. 



5d, 13? (9ov). 

 A50-39. Bahia Caledonia, Panama; Apr 26, 1939; shore. 2(^. 



Measurements. — Males, 3.5 to 10.7 mm; non-ovigerous females, 3.0 

 to 9.2 mm ; ovigerous females, 3.8 to 6.7 mm. 



Remarks. — Petrolisthes armatus is found among rocks from shore to 

 5 fathoms (Schmitt, 1935) and is frequently a member of the coral and 

 sponge faunas. 



This is a species of extremely wide distribution. In the eastern 

 Pacific it ranges from the Gulf of California to northern Peru, includ- 

 ing the Galapagos Islands. In addition, it occurs in the Indo-Pacific 

 along with some closely related species, and there is considerable dis- 

 agreement among various authors as to the status of the Indo-Pacific 

 forms. Ortmann (1897) and Borradaile (1898) are two who discuss 

 this problem. References to Indo-Pacific forms which may apply to 

 P. armatus are not included in the synonymy above. 



