﻿126 



AMPIIIURA PUGETANA. 



greenisli-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 specimens 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 part of their 

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

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

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

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

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

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

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

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

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



LIST OF SPECIMENS. 



Ciit.aloiiue Oi-iffioal I Number 

 Number. Number.l of Spec. 



Whence obtained. 



Museum of Comparative Zoology. 



12-|-l Mendocino, Cal. I I Alex. Asjassiz. 



1 Puset Sound. Dr. Kcnnerly. 



. . CaEfornia. | I 



Smithson ian Institution. 

 Puget Sound. 

 Puget Sound. 

 Puget Sound. 



Dr. Kennerly. 

 Dr. Kennerly. 

 Dr. Kennerly. 



