EUDOXOCHITON. 193 



of a dense, porcellanous texture. The laciniated insertion-plates, 

 cut into many short teeth, combined with the harshly setose girdle 

 and continuous sutural-plates, are the most striking generic char- 

 acters. 



From Acanthopleura and Maugeria, groups to which some 

 authors have referred the type of this genus, Eudoxochiton is 

 sundered by the lack of eyes in the valves, the multiplicity of slits, 

 depressed mucro, etc. 



Besides the following, Ch. linter (CLem.) Reeve may belong to 

 this genus, but its generic characters are entirely unknown. See 

 appendix. 



E. NOBILIS Gray. PI. 46, figs. 88-95. 



Shell oblong, elevated, the valves well arched, and very obtusely 

 angular on the dorsal ridge, side-slopes convex. Color uniform dark 

 brown, a little mottled toward the beaks, and marked with scarlet 

 there ; girdle rusty-brown. 



Valves broadly A-shaped, not beaked, the lateral areas moder- 

 ately raised, smooth except for the microscopic granulation and a 

 few excessively indistinct radii. Central areas having indistinct 

 growth-lines. Posterior valve (figs. 92, 93, 94) elevated in front, the 

 mucro flat, central ; posterior margin gently emarginate behind. 



Interior porcelain-white, immaculate ; smooth and poreless. 

 Sutural plates squared, continuous across the sinus, which is indicated 

 by a median bay or notch. Insertion-plates having broad, blunt 

 edges, irregularly and deeply pectinated, and having in the head- 

 valve 30, median valves 3-4, tail- valve 24-25 short slits. Eaves 

 very narrow, deeply grooved along the teeth and slightly spongy 

 there. 



Girdle (fig. 95) leathery, rust-colored, bearing short rigid black 

 spinelets. Length 60, breadth 35 mill. ; divergence 100-110. 



Auckland, Cooks' Strait ; Martin's Bay, New Zealand. 



Acanthopleura nobilis GRAY, in Dieffenbach's New Zealand, ii, p 

 245 (1843). Chiton (Eudoxochiton) nobilis Gray, SHUTTLW., Bern. 

 Mittheil. 1853, p. 67. Chiton (Chcetopleura') nobilis Gray, SMITH, 

 Zool. Erebus and Terror, p. 4, t. 1, f. 8 (1874). BUTTON, Man. N. 

 Z. Moll., p. 115 (1880.) 



This species differs from the following in its more elongated and 

 much more elevated contour, and in the stronger valves. The 

 13 



