CHITON.—Puater XXVIII. 
Species 191. (Mus. Hanley.) 
CHITON CINEREUS. Chit. testd ovatd, valvis terminalibus 
ceterarum areisque lateralibus decussatim striatis et 
basem versus concentricé sulcatis areis centralibus sub 
lente subtilissimé reticulatis ; albidd, cinereo nebulosé 
et lineata ; ligamento minuté squamoso. 
Tur asHy Curton. Shell ovate, terminal valves and 
lateral areas of the rest decussately striated and con- 
centrically grooved towards the base, central areas 
very minutely reticulated under the lens; whitish, 
clouded and lineated with ash colour; ligament mi- 
nutely scaled. 
Linn £us, Syst. Nat. p. 1106. 
Chiton cimex, Chemnitz. 
Var. C. albus, Montagu. 
C. asellus and aselloides, Lowe. 
Hab. Britain. 
The most marked variety of this species appears to be 
that in which the dark painting is disposed in longitu- 
dinal lines or stripes. 
THE STRIPED Cuiton. Shell oblong-ovate, minute, 
valves smooth or, under the lens, very finely reticu- 
lated; beautifully mottled and striped with blueish 
green and yellow; ligament very minutely scaly, 
marbled. 
Hab. Port Lincoln, Australia. 
A very minute species distinguished by the same rich 
‘display of colours which usually characterizes those of 
Australian birth. 
Species 194. (Mus. Cuming.) 
CHITON INCARNATUS. Chit. testdé ovatd, valvis levibus, 
umbonibus subrostratis, areis lateralibus subobscureé 
concentrice striatis, valvd terminali posticd subretusd ; 
incarnato-rosaced ; ligamento squamuloso, rufescente 
alboque marmorato. 
THE FLESH-TINTED CuIToN. Shell ovate, valves smooth, 
umbones slightly beaked, lateral areas somewhat 
obscurely concentrically striated, posterior terminal 
valve rather blunt ; fleshy pink, ligament finely scaled, 
marbled with pale red and white. 
? 
Species 192. (Mus. Cuming.) Hab. 
CHITON viIRGATUS. Chit. testd oblongo-ovatd, minuté, 
valvis levibus aut sub lente subtilissimé reticulatis ; 
ceruleo-viridi et luteo pulcherrimé maculata et virgata ; 
ligamento minutissimé sqguamoso, marmorato. 
Not being able to refer this shell to any of the previous ° 
species, I venture to describe it as new. 
Note. During the progress of this monograph, a Paper has appeared in the Proceedings Zool. Soc. May, 1847, by Mr. J. E. Gray, 
in which the author proposes to divide Chzton and Chztonellus into fifteen genera, according to variations of form, colour, and sculpture, 
and the length and position of the gills; the same characters indicated by De Blainville for the sectional arrangement of the species in Dict. 
Sci. Nat., 1825. The vast number of species since acquired enabling Mr. Gray to enlarge upon the plan of subdivision of the learned author 
of the ‘ Traité de Malacologie,’ he proposes to elevate each section there notified to the rank of a genus, with the following names :—Chiton, 
Tonicia, Acanthopleura, Schizochiton, Corephium, Plaxiphora, Onithochiton, Enoplochiton, Mopalia, Katharina, Cryptochiton, Crypto- 
conchus, Amicula, Acanthochites, and Chitonellus. 
None of these genera, which, it will be observed, are of very unequal rank, can be said to be founded on any new consideration of the 
animal, or upon any other character, than that exhibited in the dried specimens represented in this monograph. It has long been decided that 
variations of colour and sculpture are quite inadequate to the formation of genera, and, as our knowledge of “the length and position of the 
gills” is still limited to the observations of De Blainville on the Lamarckian types of Chiton and Chitonellus, any disturbance of the nomen- 
clature should be avoided. 
It is much to be regretted that a desire to taste prematurely of the pleasures of generalization should so frequently elicite the sudden appre- 
hension of characters for generic purposes, which, in reality, are no more than the simplest modifications of specific affinity. 
