CHITON. 
Puate I. 
Genus Curton, Linneus. 
Testa oblongo- vel elongato-ovatd, octovalvis, valvis inmvicem 
mobilibus, seepissime transversim angustioribus, convexis, 
medio umbonatis, lateraliter subalatis, in cute cartila- 
gined affixis, cute aut complanatd, aut squamatd, aut 
hispidd, aut spinosd, aut fasciculaté, interdum late ex- 
pansa, postice incisd, interdum valvis omnino obtegente. 
Shell oblong or elongately ovate, eight-valved, valves 
moving upon one another, most frequently the nar- 
rower transversely, convex, wnbonated in the middle, 
somewhat winged on each side, fixed in a cartila- 
ginous cuticle, which is smooth, squamate, hairy, 
spinous, or fasciculate, sometimes widely expanded, 
and cut at the posterior extremity, sometimes entirely 
covering the valves. 
No animals, among the retired inhabitants of the ocean, 
so long eluded the pursuit of the naturalist, as those which 
are the subject of the present monograph; dwelling in 
almost every sea short of the circumpolar temperature, yet 
very unevenly distributed throughout this extended range, 
the Chitons pass their sedentary existence in situations 
secure from displacement, and which it has been reserved 
to the zeal of recent travellers to penetrate. Little did it 
occur to the great reformer of the Linnean school when 
recording, so late as 1819, in the sixth volume of his ‘Ani- 
maux sans vertébres’, a list of only six species, that nearly 
ten times that number were dwelling in retirement on the 
western shores of the Pacific, that as many more were 
living secluded among the rocks of Australia and New 
Zealand, and that the sum of these united would in twenty 
years be nearly doubled, by the discovery of species in other 
localities; yet such are the fruits of recent voyages, and 
the spirit of research which has accompanied them. 
It must not be supposed that of probably two hundred, 
more or less, distinct species of Chiton, and nine or ten of 
Chitonellus, which I have now under investigation, only 
seven were known to Lamarck ; upwards of twenty distinct 
kinds were figured thirty years before by Chemnitz in the 
‘Conchylien Cabinet’; some of these are indecipherable, 
but others, since left in obscurity, I have succeeded in 
identifying. 
As a proof that the cabinets of Paris were singularly 
meagre in their collections of this genus, it is worth re- 
marking that most of the species figured in the ‘ Encyclo- 
pédie Méthodique’, are copied from the ‘Conchylien 
Cabinet’, and rendered not the less ambiguous by the 
transfer. Lamarck, at the time of his occupation on the 
genus, was afflicted with blindness, and, touching the cir- 
cumstance of his only being able to identify five out of the 
five and twenty represented in the ‘ Encyclopédie’, ob- 
serves “Ce genre est fort nombreux en esptces, mais, 
malheureusement, privé de la vue, et hors d’etat de con- 
stater nous-mémes les caractéres des esptces, nous n’en 
citerons qu’un petit nombre parmi celles que nous possé- 
dons.” 
The first addition to the tropical species of the genus, 
was made through the researches of Mr. Frembly, on the 
coast of Chili, in 1825, recorded in the 3rd volume of the 
‘Zoological Journal’; these were multiplied to an unpre- 
cedented extent by the indefatigable exertions of Mr. 
Cuming, in the same and adjacent localities, and subse- 
quently in the Philippine Islands; whilst the inventory of 
species has been increased to its present magnitude, 
through the zealous assiduity of M. Quoy, in the Sur- 
veying Expedition of the ‘Astrolabe’, of Captain Sir 
Edward Belcher in the several Surveying Expeditions 
of the ‘Blossom’, the ‘Sulphur’ and the ‘ Samarang’, of 
the Rev. W. V. Hennah, resident at the Cape of Good 
Hope, of Dr. Dieffenbach and Mr. Earl, in New Zealand, 
of Mr. Gunn, in Van Dieman’s Land, and of Capt. Ince, in 
Australia; it must not be forgotten also that some few 
contributions have been made to the genus by Dr. Gould, 
Mr. Courthouy, and other naturalists of the United States, 
as well as from the shores of our own coast through the 
dredging exertions of Professor Edward Forbes and Mr. 
Me’ Andrew. 
Regarding the soft parts of Chiton, two very opposite 
theories were advanced by contemporary authors; one by 
Linnzus, founded on the multivalve structure of the shell, 
in which he assigned the genus to a place among the 
Lepades ; the other by Adanson, drawn from observations 
made on the shores of the Mediterranean a few years sub- 
sequently, in which he transferred the Chitons to the im- 
mediate vicinity of the Patelle. The conclusions of the 
philosopher in the closet, were destined, however, to be 
overthrown by the observations of the naturalist in the 
field; the views of the illustrious traveller in Senegal 
having been confirmed many years after by Cuvier, not- 
withstanding the opposite opinions entertained by nume- 
rous intervening writers. ; 
March, 1847. 
