CHITON.—Puate X. 
Tne Srrxa Curron. Shell elongately oblong, valves 
smooth, shield-shaped, lobed posteriorly on each side, 
the posterior terminal valve umbonated at the extre- 
mity, the anterior small, distinguished at the margin 
by half a dozen rather distant notches ; snowy white ; 
mantle large, spread entirely over the shell, very 
beautifully and thickly beset with minute stars of 
glassy spicule. 
Hab. Sitka, New Archangel; Lady Katherine Douglas. 
The mantle of this gigantic species of the Amicula type, 
is studded with minute stars of glassy spicule, which 
appear to be radiately displayed or closed at the will of 
the animal; when displayed their appearance reminds one 
of the star-like pattern in the mineral Wavelite. The 
valves being entirely enveloped by the mantle, which is 
impermeable to light, are destitute of colour, and, as in the 
rest of the group, are produced on each side posteriorly 
into lobes. 
Species 56. (Mus. Cuming.) 
CHITON PORPHYRETICUS. Chit. testd subelongato-ovatd, 
valvis medio punctatis, utringue verrucoso-scabris, 
costd unicd ad marginem arearum lateralium, valva 
terminali anticd radiatim quinquecostata, postica parva, 
retusd ; cinereo-purpured, macula conspicud luted, mar- 
gine nigro-punctaté, medio vivide purpured per summi- 
tatem umbonalem utriusque valve ; ligamento coriaceo, 
valvarum latera partim obducto, cristis parvis ornato. 
THE PURPLE Cuiton. Shell somewhat elongately ovate, 
valves punctured in the middle, verrucosely rough on 
each side, with a single ridge along the edge of the 
lateral areas, anterior terminal valve radiately five- 
ribbed, posterior small, blunt ; cinereous purple, with 
a conspicuous yellow spot, dotted with black at the 
edge and stained with bright purple in the middle, 
along the umbonal summit of each valve ; ligament 
coriaceous, spreading partially over the sides of the 
valves, and furnished with small tufts. 
Acanthochetes violaceus, Gray, Appendix to Dieffenbach’s 
New Zealand; (not C. violaceus, Quoy). 
Hab. New Zealand. 
A beautifully painted species easily distinguished by the 
bright purple colouring of the umbonal summit, which 
appears constant in all the specimens I have seen; the 
punctures of the central portion of the valves also afford 
an unusual contrast with the rest of the surface which is 
raised in small warts. 
Species 57. (Mus. Cuming.) 
CHITON MONTICULARIS. Chit. testd elongato-ovaté, valvis 
levibus, medio carinatis, postice wmbonatis, utringue 
laté biradiatim costatis ; albé ; ligamento corneo, nigro, 
cristis brevibus munito, testam nisi umbones obducto. 
THE moNTIcULAR CuiTon. Shell elongately ovate, 
valves smooth, keeled down the middle, umbonated 
posteriorly, with two widely radiating ribs on each 
side; white; ligament horny, black, furnished with 
short tufts, spread over the shell except at the um- 
bones. 
Quoy and Garmarp, Voy. de |’Astrolabe, Zool. vol. 3. 
p. £06. pl. 73. £. 30-35. 
Hab. New Zealand. 
The shell of this species is enveloped by a thin expan- 
sion of the mantle after the manner of the C. amiculatus 
and Hmersonianus, a small compressed umbone only ap- 
pearing through it in place of the raised heart-shaped shield. 
T do not see, with M. Deshayes, that this proves the in_ 
utility of the genus Chitonellus; the valves are enframed 
within the ligament, and their arrangement is the same as 
in the typical form of Chiton. 
One peculiarity of this species is, that the row of short 
tufts are situated about midway between the umbonal 
summit and lateral margin of the shell. 
