186 CHITON. 



Girdle solid, closely covered with smooth, convex scales. 

 Length 43, breadth 25 mill. ; divergence 105. 

 Length 38, breadth 27 mill.; divergence 100. 

 Length 33, breadth 24 mill.; divergence 112. 



Cape of Good Hope. 



Chiton tulipa QUOY & GAIMARD, Voy. de 1'Astrol. Zool., iii, p. 

 389, t. 74, f. 35-36 (1834). KRAUSS, Die Siidafric. Moll., p. 37. 

 C. cymbiola SOWERBY, Charlesworth's Mag. of Nat. Hist. 1840, p. 

 292 ; Conch. Illustr., f. 45, and var., f. 85, 86. REEVE, Conch. Icon., 

 t. 3, f. 18. 



? C. politus SPENGLER, Skrivter af Naturhist.-Selskabet, iv, p. 

 89, 1797. 



A smooth, polished species, excessively variable in color and 

 pattern. The short traces of grooves at the diagonal line are rarely 

 visible without a lens, and are completely obsolete in many spec- 

 imens. The smooth surface and unusual coloring are the more 

 striking characters of the species ; but the strongly raised lateral 

 areas and the central mucro at once separate it from C. Icevigatus, 

 marmoratus, etc. 



C. RUSTICUS Deshayes. PL 31, figs. 32, 33, 34. 



Shell ovate-oblong, depressed, the jugum rounded ; very dark 

 green, much paler beneath. 



Entire surface quincuncially granulose. Central areas with no 

 other sculpture, but at the diagonal line there are on each side 10-15 

 very short but deep grooves. Lateral areas swollen, and having a few 

 indistinct, obsolete swelling ribs, or rather, obsolete knobs irregularly 

 coalescing in to* indistinct ribs; blotched with paler. End valves 

 similarly sculptured and blotched, beak of the tail valve in front of 

 the middle, the slope behind it a trifle concave. 



Interior: anterior valve having 9, central valves 1, posterior 

 valve 12 slits; teeth pectinated ; eaves short; sinus moderate, with 

 about 13 teeth. 



Girdle dark olive, like the valves ; covered with very large stout 

 scales. 



Length 24, breadth 15, alt. 6 mill. 



Length 20, breadth 13 mill.; divergence 115. 



I ii-ii ii ion and 



