474 



CIIITOKINi^E. 



the species inhabit Greenland, Peru, Chili, the Philip- 

 pine Islands, and New Zealand. 



Species of Tonicia. 



atrata, Sow. 

 Brandtii, Midd. 

 Chilensis, Frembl. 

 Chiloensis, Sow. 

 crenulata, Brad. 

 disjuncta, Frembl. 

 elegans, Frembl. 

 Eschscholtzii, Midd. 

 fastigiata, Gray. 

 granifera, Sow. 



Grayi, Sow. 

 insignis, Reeve. 

 lineata, Wood. 

 lineolata, Frembl. 

 marmorea, 0. Fabr. 

 ]\Ierckii, Midd. 

 picta, Reeve. 

 Sitchensis, Midd. 

 Svvainsoni, Soiv. 

 truncata, Sow. 



Genus CHITON, Linnasus. 



Mantle densely beset with unequal, corneo-calcareous, 

 often very long spines, or with small, calcareous spicula, 

 giving it a spinulose appearance. 



Shell with the valves external, broad, transverse ; the 

 hinder valve with the apex sub-central, 



Si/ii. Scutigerulus, Meusch. Acanthopleura, Guild. 

 Canthapleura, Swains. Corephium, Gray, not Browne. 



Ex. C. brevispinosus, Sowerby, pi. 54, fig. 1. C. 

 aculeatus, Linnceiis, fig. 1, a. 



The calcareous nature of the spicula which cover the 

 mantle-margin, will at once distinguish the species of this 

 genus from those of Chcetopleura, in which they are 

 horny. The plates of insertion of the terminal valves 

 are many-lobed, of the posterior sometimes somewhat 

 obsolete, and of the middle bi-lobed. The Corephiwn of 

 Browne, figured previously by Petiver under the name 

 of Asellus marinns, is a Crustaceous animal. 



