AMPHIURA PUGP:TANA. 



125 



LIST OF SPECIMENS. 



Amphiura pugetana Lyman. 



Amphiurn pugetana Lymax. Proceed. Boston Soc. Nat. Hist., VII. p. 103. 



Special Markx. — Arms long ; often eight times the diameter of the 

 disk ; a hght hne running along their upper side. 



Description of ci Specimen. — Diameter of disk, 3.5°"° ; from outer 

 edge of mouth-shield to outer corner of opposite mouth-slit, 1.5™° ; 

 greatest width of arm without spines, .7""" ; length of arms, 24.5"""' ; 

 distance from outer side of inouth-shield to inner points of mouth- 

 papilla), to that between outer corners of mouth-slits, .6 : .5. Teeth 

 four, stout, flat, rather thick, squarish, with cutting edge curved. 

 Mouth-shields nearly diamond-shaped, the outer and side angles slightly 

 rounded ; length to breadth, .3 : .2. Side mouth-shields large, thick, and 

 somewhat swelled ; meeting within, closely joined to surrounding parts. 

 Under arm-^Dlates five-sided, with the fifth angle directed inward • length 

 to breadth, near base of arm, .5 : .4. Side arm-plates strong and well 

 developed, meeting above and below. Upper arm-plates bounded within 

 by a strong arch, without by a slight curve ; their lateral sides short ; 

 length to breadth, near base of arm, .5 : .7 ; they do not quite touch 

 each other. Scales of disk mostly rounded, smaller below than above ; 

 those above of pretty even size, with a few little ones ; near edge of 

 disk, aljout 50 to a square mm. ; those toward the centre larger. Radial 

 shields closely joined for their whole length, oval, with the inner end 

 pointed ; length to breadth, .7 : .3, Arm-spines three, sometimes four 

 on joints close to disk ; evenly tapering, moderately stout, of even 

 lengths ; length near disk, .5"""'. Tentacle-scales two, small and rounded, 

 placed obliquely side by side. Color, in alcohol : disk, above, light 



