ISCHNOCHITON-RADSIELLA. 139 



yellowish or greenish, and regularly spotted with brown. The foot 

 is narrow, yellowish ; the gills almost reach the head. 

 Length 18, breadth 12, alt. 4 mill. 



Port Carter et, New Ireland. 



Chiton tessellatus Q. & G., Voy. de PAstrol., Zool. iii, p. 396 ; 

 atlas, t. 75, f. 43-47. 



The description is from that of Quoy and Gaimard. The coloring 

 is probably less vivid than shown in their plate. The artist of the 

 ' Astrolabe ' seems to have had an irrepressible fondness for green. 



I. ARBUTUM Keeve. PI. 24, figs. 16, 17. 



Shell ovate, terminal valves and lateral areas of the rest reticulately 

 decussated with grained stride diverging off posteriorly ; central areas 

 very closely sculptured with blunt squarish granules ; green or red- 

 dish, dotted with black ; ligament squamately coriaceous, tessellated. 

 (five.) 



Port Essington. 



C. arbutum Rv., Conch. Icon., t. 24, f. 162. 



Carpenter thinks this is probably a color variety of J. adelaidensis. 

 He gives the following notes on the 8 specimens in the Cuming 

 collection : Shell ovate, tolerably elevated, rather broad ; jugum 

 more or less obtuse. Reddish orange, olivaceous or light ash, more 

 or less spotted and clouded, but always with a very fine tessellation of 

 dark and light along the sutures. Mucro in front of the middle, 

 the slope behind it concave ; intermediate valves oblong, not beaked ; 

 central areas coarsely and very regularly quincuncially granulated 

 with large grains ; lateral areas very slightly raised, with about 6 

 rows of larger grains. End valves with similar grains, which are 

 radiating but scarcely in lines. Interior: anterior valve having 



II, central valves 1, posterior valve 16 slits: teeth quite sharp, 

 typically Ischnoid ; eaves large, not spongy. Girdle tessellated with 

 olive and light, covered with imbricating short roundish and quite 

 smooth scales. Length 12 i, breadth 8 mill. 



Section Radsiella Pilsbry, 1 892. 



Radsiella PILS., Manual of Conch. (I) xiv, p. 54 (July 25, 1892). 

 Type, /. tridentatus Pils. 7sc/morac?sm CARPENTER MS. and DALL, 

 Proc. U. S. Nat. Mus. 1878, p. 331. Not Ischnoradsia SHUTTLW., 

 1853. 



Valves and girdle entirely similar to those of the normal Ischno- 



