NO. 2 WALTON : THE GENUS PYLOPAGURUS 143 



Specimens in the Hancock collection are from San Miguel Island, 

 Santa Cruz Island, Santa Barbara Island, Santa Catalina Island, San 

 Clemente Island, California, and Baja California, Mexico; and from 

 Inner Gorda Bank, Coronados Island, Natividad Island, Angeles Bay, 

 San Pedro Nolasco Island, and Lobos Point, Gulf of California, Mexico. 



This species was taken at the following Hancock stations. The num- 

 ber of specimens is indicated after each station number : 



The San Miguel Island record at 34°05'20" N. Latitude and 120° 

 20'40" W. Longitude represents a slight northward extension of the 

 known range of the species. The southward records to the tip of Baja 

 California and thence northward into the Gulf of California constitute 

 a very considerable extension of the known range and indicate a unique 

 geographic distribution. The bathymetric range is quite wide, from one 

 fathom to 250 fathoms. 



Discussion : A considerable degree of sexual dimorphism is ex- 

 hibited in this species. The females tend to be more slender and have the 

 major hand longer in proportion to its width ; this results in the opercular 

 face of the manus approaching an ovoid rather than a discoidal out- 

 line, with the terminal end slightly flattened. The difference is further 

 heightened in old males, apparently as a result of isogonic growth. After 

 maximum size is attained, further laying down of calcium carbonate 

 builds up the margins of the hand, the resultant high ridge imparting a 

 very concave surface to the hand, although otherwise the relative pro- 

 portions remain unchanged. 



Remarks'. The favored carcinoecium seemed to be shells of Den- 

 talium sp. although some were found in a tubular bryozoan colony, 

 Antropora tincta (Hastings). 



