﻿HuTTON. — Ooi the New Zealand Cliitonidse. 175 



the Chitons on tliem, wrapped np in separate pieces of paper. On arrival at 

 home they should be placed in a basin of fresh water for a short time, then 

 removed, and either tied down to the stones with string, or a light weight put 

 on each, and put into a dry place. After two or three days, when the margin 

 has got quite hard, they can be easily removed from the stones, an ohe animal 

 taken out, and after another day or two for the interior to dry, they will be 

 ready for gumming down on to cards, on which the name, locality, date of col- 

 lecting, and the position in which they were found, should be written. 



The genera are founded upon the shape and covering of the mantle ; the 

 species chiefly on the shape and sculpturing of the valves, which latter is easily 

 made out with the aid of a pocket lens. The colour varies very much, and 

 can never be taken as a specific distinction, although in many cases it may 

 assist the beginner in naming his collection ; those of the margin of the mantle, 

 and of the spines upon it, are, however, much more constant than those of the 

 valves. The shape, or the pi'oportion of breadth to length, is generally pretty 

 constant, but the size of individuals, especially the larger kinds, varies con- 

 siderably, and too much weight must not, therefore, be attached to it. The 

 shape of the posterior margin of the valves will also be often found very useful 

 when the specimen is rubbed or eroded. The teeth on the tongue, and the 

 branchial laminse are also of great importance in determining the species, but 

 as these parts are not easily examined and preserved, they will not be found to 

 be so useful as the other characters. 



Chitons are found in all countries, but they are not so abundant in the 

 northern hemisphere as in the southern, nor on the shores of the Atlantic as 

 on those of the Pacific, neither are they so common nor so large in cold 

 latitudes as in warm, the sub-tropical portion of the South Pacific appearing to 

 be their head-quarters. In England only about a dozen species have been 

 found, while twenty-one ai-e here described as already known to inhabit New 

 Zealand, and undoubtedly many more have yet to be discovered, for, with the 

 exception of M. Quoy in the '■ Astrolabe,' and the late Dr. Sinclair, few people 

 have collected them. Altogether nearly 300 species are now known to science. 



In a fossil state about twenty-four species have been found, some of them 

 dating so far back as the Upper Silurian period. 



I have not thought it necessary to give figures of the difierent species, for, 

 with a moderate amount of attention, they will be readily made out from the 

 descriptions, and I quite agree with Messrs. Kirby and Spence that they who 

 begin their zoological studies by turning over figures usually end them there, 

 and never attain to that nameless t.ict in making out species that can only be 

 the result of j)atient study.* 



Introduction to Entomology," Vol. IV., p. 569. 



