from Chili. 199 



obtuse, and embracing the carina. Border rather narrow, granu- 

 lated, shining, greenish, divided into two parts, the upper having 

 the smallest granulations, which in both are placed transversely. 



Length two inches, breadth 1-^3^; found plentifully at Valpa- 

 raiso under stones in still water. 



A variety of this species occurred, differing in these respects 

 from the above description. Shell thicker, back more raised, and 

 the posterior compartments of the dorsal valves less distinct. A 

 specimen also was found shewing on the outside only seven valves, 

 but inside the articulation of the other valve Mas plainly seen. 



I liave named this species after my friond Mr. Cumings, of 

 Valparaiso, whose zeal in the pursuit of this interesting science 

 will, I am persuaded, soon make a large addition to our present 

 stock. 



4. Chiton olivaccus. 



C. testa ovali, lata, olivacea, a;ruginoso-punctulata; valva antica, 

 posticaque radiatim-striatis ; areis valvarum ccntralibus longL- 

 tudinaliter sulcatis, latcralibus radiatim striatis.. 



Tab. Supp. XVr. f. 4. 

 Syn. Chiton latus. Sowerby in T. C. No. 692. 



Shell opaque, ovate, olivaceous, dull, dotted with lighter co^ 

 loured spots : inside glaucous. Valves eight, the anterior one 

 Mith regular radiating striae, crossed by concentric ridges; pos- 

 terior margin nearly straight. Dorsal valves obtusely beaked, 

 divided laterally into two compartments ; the anterior having re- 

 gular longitudinal striae, crossed with others very minute and con- 

 centric ; from under the beaks diverge to the lateral margins of 

 the valves coarser and more irregular stria;, which raise the pos- 

 terior compartment above the other. The posterior valve has a 

 well defined apex, leaning towards the posterior margin. Uorder 

 thin, moderately broad, and covered with fine shining bead-like 

 granulations, of the same colour as the shells, divided into two 

 distinct portions, the upper of which is composed of nmch finer 

 beads than the lower, and which, as in the last species, are placed 

 transversely. 



