22 



Crustacea and Echinodermata of the 



Locality. 



Sex. 



Length of 

 Carapax. 



Width of 

 Carapax. 



San Francisco, 



$ 



2.95 inch. 



4.90 inch 



it It 



it 



2.56 



4.18 



it tt 



a 



2.47 



4.01 



" " 



a 



2.46 



4.00 



Tomales Bay, 



" 



2.35 



3.78 



San Francisco, 



" 



2.27 



3.66 



" " 



" 



2.10 



3.36 



a a 



t( 



1.97 



3.05 



" " 



tc 



0.99 



1.29 



a a 



9 



2.84 



4.30 



Tomales Bay, 





2.73 



4.20 



San Francisco, 





2.15 



3.34 



Tomales Bay, 





2.16 



3.32 



ii i< 





2.00 



3.07 



Proportion. 



1:1.63 inch. 



1:1.63 



1:1.62 



1:1.62 



1:1.60 



1:1.60 



1:1.60 



1:1.55 



1:1.30 



1:1.52 



1:1.54 



1:1.55 



1:1.54 



1:1.54 



Here it will be perceived that the male is wider than the 

 female ; and also that the males steadily increase in width 

 with age, while the females show some variation. The 

 great breadth in this species renders it easily distinguishable 

 from its congeners. 



Distortions of the antero-lateral teeth often occur, render- 

 ing the sides somewhat unsymmetrical. 



This Cancer is common at San Francisco, and is sold in 

 the markets with C. mag-ister. It was also found at Tomales 

 Bay by Mr. Samuels, and in Puget Sound by the Explor- 

 ing Expedition. 



Mus. Bost. Soc. ; Smithsonian ; Phil. Acad. ; Paris ; 

 Acad. Petrop. 



CANCER ANTENNARIUS. StimpSOn. 



Plate XVIII. 



Cancer antennarius, Stimpson ; Proc. Cat. Acad. Nat. Sci. i. 88. 



Carapax convex ; greatest breadth at the penultimate 

 antero-lateral tooth. Superior surface much undulated, 

 very smooth in appearance, but minutely granulated ; the 

 granulation being almost obsolete about the middle, but 

 sufficiently well marked towards and at the margin. Antero- 



