250 ONITHOCHITON. 



middle, the interstices very narrow. Anterior valve having about 

 20 radii, much smaller than those of the lateral areas, but toward 

 the sutures becoming coarser than those of the lateral areas. Poste- 

 rior valve depressed, the mucro subterminal. 



Interior: anterior valve having about 9 slight slits, not corre. 

 spending to the outside dots. Central valves with 1 slit ; teeth 

 striated outside and at the broad, but sharp edge. Eaves planed off, 

 scarcely grooved. Sinus broad, deep, with about 14 denticles. 



Girdle stout, with shelly spines, exactly like magellanicus, prin- 

 cipally whitish, irregularly tessellated with dark. (Cpr., from 

 type.) Length 18, breadth 10 , divergence 90. 



Nine or Savaye Island, Friendly Group (Brenchlev.) 



Chiton ( Onithochiton) amicorum BAIRD, in Brenchley's Jotting* 

 during the Cruise of H. M. S. 'Curacoa' among the South Sea 

 Islands, in 1865. London, 1873, p. 445, t. 40, f. 7. 



The generic position of this species is uncertain, but could be 

 readily ascertained by an examination of the type, which is, we 

 believe, in the British Museum. It is probably either an Onithochiton^ 

 a Liolophura or a Plaxiphora. Baird's original description is as 

 follows: "Shell ovate, nearly equal at each extremity; mantle 

 margin covered with numerous chaffy-looking scales, first valve 

 larger than any of the others, marked with numerous granular lines ; 

 central valves strongly striated, lateral areas with 2 or 3 granular 

 lines ; last valve small and striated. A line of a red color runs 

 along the top of all the valves, whilst "one or two others run along 

 the lateral areas. Length 8 lines, breadth 5J lines." 



O. MAILLARDI Deshaves. PI. 55, fig. 20. 



Shell oblong, elevated, the dorsal ridge roundly angled, side- 

 slopes nearly straight. Surface shining ; color pale buff, with a nar- 

 row orange-tinted or brown triangle at the ridge of each valve, 

 several dark -green spots along each diagonal slope, the lateral areas 

 and head valve with concentric green-olive sometimes dark brown 

 lines. 



Median valve beaked, the lateral areas somewhat raised, having 

 near the front margin a narrow radiating band of eye-dots, the width 

 of the band greater on the hinder valves; sculptured with longitu- 

 dinal grooves corresponding with the dark color-lines, sometimes 

 irregular or branching; and continuing upon the diagonal slope. 

 Upon the central areas these grooves become much more delicate,. 



