Eudoxochiton. \ AMPHINEURA. 4:1 



From Acanthopleura and Maug&ria 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, &c. 

 (Pilsbry.j 



This genus seems to be restricted to New Zealand. Pilsbry states 

 that C. linter, Keeve, from the East Indies, may belong to this genus, 

 but its generic characters are entirely unknowji. 



KEY TO SPECIES. 

 a. Shell elevated, divergence 100-110, anterior valve with 30 slits, 



spinelets black . . . . . . . . . . . . nobilis. 



a. Shell depressed, divergence 135-140, anterior valve with 17 slits, 



spinelets brown . . . . . . . . Huttoni. 



1. Eudoxochiton nobilis, Gray, 1843. Plate 2, figs. 20, 25 ; Plate 4, 



fig. u. 



Acanthopleura nobilis, Gray, Dieff. N.Z., ii, 245. Eudoxochiton nobilis, 

 Gray. Man. Conch. (1). xiv. 193. pi. 4(5, f. 88-95; Ereb. & Ter., 

 pi. i, f. 8; P. Mai. S., ii, 197. 



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

 angular on the dorsal ridge, side slopes convex, smooth, dark brown. 

 Anterior valve with about 15 indistinct low radiate ribs. Intermediate 

 valves broadly A-shaped, not beaked, the central areas smooth except 

 for very fine close growth-lines ; lateral areas moderately raised, with 

 3-5 indistinct radiate ribs. Posterior valve elevated in front, the 

 mucro flat, central ; posterior margin gently emarginate behind. All 

 valves microscopically punctured. Girdle leathery, rust-coloured, 

 bearing short rigid black spinelets. Colour uniform dark brown, 

 a little mottled toward the beaks and marked with scarlet there ; 

 girdle rusty-brown. Interior porcelain-white, immaculate, smooth and 

 poreless ; anterior valve having 30, median valves 3-4, tail valve 

 24-25 short slits ; insertion plates with broad, blunt edges, irregularly 

 and deeply pectinated ; sutural plates squared, continuous across the 

 sinus, which is indicated by a median bay or notch ; eaves very narrow, 

 deeply grooved along the teeth, and slightly spongy there. 



Length, 60 mm. ; breadth, 35 mm. Divergence, 100-110. Other 

 measurements are 75 mm. by 45 mm. ; 110 mm. by 62 mm. ; 123 mm. 

 by 70 mm. 



Type in the British Museum. 



Hab. East coasts of North and South Islands ; on rocks or under 

 boulders in exposed situations, sometimes together with Plaxiphora 

 biramosa and P. obtecta. A rather rare shell. 



2. Eudoxochiton Huttoni, Pilsbry, 1893. Plate 4, fig. 15. 



Eudoxochiton Huttoni. Pilsbry, Man. Conch. (1), xiv, 194, pi. 46, f. 96-100. 



Shell oval, depressed, with convex side slopes, brown, smooth, with 

 microscopic punctulation. Anterior valve has no trace of radiate ribs, 

 only very fine growth-lines. Intermediate valves broadly A-shaped, 



