38 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 24 



six to nine, of leg 3 with five to seven; merus of legs 1 and 2 with a 

 posterodistal spine. 



Sternum, sternal plastron, abdomen, and ventral surface of cheli- 

 peds and walking legs covered with strong striations. 



Material examined: See Table 6. 



Measurements: Males, 6.9 to 17.4 mm; non-ovigerous females, 6.1 

 to 11.1 mm; ovigerous females, 7.3 to 13.2 mm. 



Color: In recent alcoholic specimens the transverse ridges and 

 squamiform tubercles of the carapace are dark red, the intervening 

 spaces yellowish. Lower surface, including abdomen, deep madder. 

 (Faxon) 



Ecology: In the Atlantic the species has been reported to a depth of 

 27 fathoms, and in the littoral under stones and associated with 

 sponges, corals, and anemones. Collection data for Pacific specimens, 

 much of which are incomplete, do not indicate any commensal associa- 

 tions. The Velero III dredged specimens in 4 and 10 fathoms, from 

 bottoms of sand and of sand and shell, respectively. Other examined 

 material was probably shore collected. 



Ovigerous females are reported from January, February, and 

 March. 



Remarks: Petrolisthes galathinus, which had already been collected 

 many times in the Atlantic and described under several names, was 

 first reported from the Pacific coast by Stimpson (1858, 1859) as P. 

 occidentalis on the basis of specimens collected by Sternbergh and Rowell 

 in Panama. A number of specimens taken by those collectors and labelled 

 "Panama" were seen in the Museum of Comparative Zoology, but of 

 these only a male and three females collected by R. Rowell are labelled 

 as types. The designation "Panama" probably refers to Panama City. 



The species was also reported as Petrolisthes occidentalis by Streets 

 (1871b) from specimens collected by J. A. McNeil, and by Faxon ( 1893, 

 1895) from the collections of the Albatross. These lots of specimens 

 were also seen by the writer, the first in the Academy of Natural Sci- 

 ences of Philadelphia and the second in the U. S. National Museum. 



Ortmann (1897) was the first to regard Petrolisthes occidentalis 

 identical with P. galathinus. Under the latter name it was reported 

 from the Pacific coast by Schmitt (1935), Boone (1931, 1932), and 

 Hult (1938). The Boone and Hult records, however, refer to another 

 species. 



