TONICIA. 209 



ately concentrically subimbricately sculptured throughout; the 

 lateral areas not raised but separated from the dorsal areas by an . 

 elevated rib. Posterior valve strongly gibbous, the umbo almost 

 terminal ; mantle margin brown. Length 9 lines. (Angas.} 



Port Jackson, Australia. 



Tonwia carpenteri ANG., P. Z. S. 1867, p. 116, 223, t. 13, f. 30. 



Carpenter gives the following descriptive notes : 



One specimen without anterior valve. The specimen as it stands 

 measures length 17, breadth 15 mill. ; but measuring the valves only 

 and allowing for the missing anterior valve it would be length 16, 

 breadth 10 mill. Shell oval, moderately elevated, the dorsal ridge 

 acute; olive clouded with dark, tessellated with light so as to appear 

 toothed at the sutures. Mucro central, swelling, elevated, the pos- 

 terior slope convex. Jugal area a rather narrow, nearly smooth 

 dorsal line. Central areas with about 16 finely, rugosely sculptured, 

 nearly concentric, but faint, grooves on the otherwise smooth surface. 

 Lateral areas slightly raised by the curved diagonal ; having lines 

 of stumpy granules and concentrically rugosely grooved in continua- 

 tion of the sculpture of the central areas, obsolete at sutures. Pos- 

 terior valve concentrically grooved like the rest, all around. Girdle 

 nearly smooth, very slightly lanugate. Posterior valve with 11 

 slits ; teeth rather sharp, grooved outside ; eaves very small. Sinus 

 broad, flat, deep, having about 17 very slight teeth. 



This species is a transition toward Acanthopleura in the thrown- 

 forward teeth, but girdle and sinus are more Tonicioid. (Cjpr.) 



T. LAMELLOSA Quoy & Gaimard. PL 40, figs. 8, 9, 10, 11. 



Shell small, oval-elongate, subelevated, carinated ; valves trans- 

 versely scaly-striated, variegated with gray or ferruginous ; girdle 

 thick, smooth, reddish marked with radiating brown lines. Anterior 

 valve having 10 crenulated teeth, posterior 9, and a much project- 

 ing tuberosity. Color of valves grayish-yellow, varied with brown, 

 red or greenish. Girdle usually yellow. ( Q. & G.) 



Length 15, breadth about 8, alt. 5 lines. 



Tonga Tabu. 



Chiton lamellosus Q. & G., Zool. Astrol. iii, p. 386, t. 74, f. 29-32. 



This species has the mucro more posterior than any of the preced- 



