ONITHOCHITON. 251 



closer, converging toward the dorsal ridge, and often zigzagged ; the 

 median triangle of the central areas smooth. Anterior valve having 

 8 narrow rays of eyes, occasionally with some eyes scattered between 

 along the lower margin ; the intervals between the eye-rays sculpt- 

 ured with sulci forming short arcs of concentric grooves. Posterior 

 valve depressed, triangular ; its length from sinus to the posterior 

 terminal mucro being one-half the greatest breadth of its tegmentunu 



Interior white, with a large spot of rich brown in each valve. 

 Sinus delicately toothed, wide and deep. Anterior valve having 8 

 slits, median valves 1 slit ; teeth finely and sharply pectinated out- 

 side. Posterior valve having a smooth ledge of callus in plate of 

 the insertion-plate, flat behind, rounded at the sides. Eaves narrow, 

 grooved, solid. 



Girdle fleshy-brown, leathery. 



Length 24, breadth 15 mill.; divergence 110-115. 



Mauritus and Bourbon (Reunion.) 



Chiton maillardi DESH., Moll, de File Reunion, p. 38, t. 5, f. 14. 

 Chiton (Tonicia?) maillardi MARTENS, in Mobius' Reise nach 

 Mauritius, p. 300. Ornithochiton maillardi CPU., MS. Ornitho- 

 chiton sp., MOSELEY Quarterl. Journ. R. Mic. Soc. xxv, p. 54, t. 5 r 

 f. 4-7. 



O. LITERATUS Krauss. PL 55, figs. 21, 22, 23. 



Shell ovate, convex ; brown, spotted with whitish and having a 

 whitish longitudinal band ; closely sulcate. Interior white, brown- 

 ish-violet in the middle. Anterior valve lunate, convex with 

 undulating grooves ; posterior valve triangular, depressed, sculptured 

 with angular grooves; intermediate valves sinuated in front, 

 rounded at the sides, undulately and angularly grooved. Girdle 

 rufous-brown, leathery, velvety. 



Length 1 2, breadth 8 lines. (Krauss.") 



Natal 



Chiton literatus KRAUSS, Die Siidafrik. Moll. p. 36, t. 3, f. 6. 



I have not seen this species, which is evidently quite distinct, 

 although allied to 0. maillardi. The central areas have angular or 

 zigzag grooves ; the lateral areas are not raised, and are sculptured 

 with wavy grooves. The back is not carinated. Insertion plates as 

 usual in the genus. 



