126 



AMPHIURA PUGETANA. 



greenish-gray ; below lighter, radial shields darker ; arms, above and 

 below, straw-color, with a faint white line running lengthwise above. 



Variations. — The angles of the mouth-shields may be more or less 

 rounded. Among younger sj)ecimens the scales of the disk are more 

 even in size, and the primary plates have their corners not entirely 

 rounded off The proportion of the arms to the disk varies somewhat ; 

 thus : diameter of disk to length of arms as 3.5 : 24.5, 3 : 21, or 

 2.5 : 22.5. 



This species is distinguished from others of the genus as follows : 

 A. Orstedii has the radial shields longer, and separated a j)art of their 

 length ; four or five spines and upper arm-plates broader. A. Punta- 

 rence has rather longer arms, a small notch in the outer side of the 

 under arm-plates, and the upper arm-jDlates regularly oval. A. violacea 

 has mouth-shields proportionately much smaller, and the arms shorter ; 

 the color must also be quite distinct. A. microdiscus has, even in small 

 specimens, the upper arm-plates touching each other, and twice as broad 

 as long. A. tenera has the middle arm-spine swelled at the base. A. 

 squamata stands very near the present species ; but the arms, in speci- 

 mens of the same size, are not more than half as long. 



LIST OF SPECIMENS, 



Catalogue 

 Number. 



Original ! Number 

 Number.] of Spec. 



Locality. 



When 

 Collected. 



Whence obtained. 



Nature of 

 Specimen. 



231 

 232 



380 



1053 

 1057 

 1037 



1057 



12+ 

 1 



Museum of Comparative Zoology. 



Mendocino, Cal. 

 Piijiet Sound. 

 California. 



Smithsonian Institution. 



Puget Sound. 

 Puget Sound. 

 Piisret Sound. 



Alex. Agassiz. 

 Dr. Kennerly. 



Dr. Kennerly. 

 Dr. Kennerly. 

 Dr. Kennerly. 



Alcoholic 



Alcoholic. 



