116 CHITONIDA. 
Genus, MOPALIA—Gray. 
Mantle moderately wide, bristly or hairy, with a sinuosity on the 
hinder lower edge; valves with a small portion of the lateral areas 
covered by the mantle ; hinder valve large, with the apex sub-central, 
and posteriorly slightly sinuated ; plates of insertion of all the valves 
with a single notch on each side. 
M. ciliata, Sowerby ; Reeve, Conch. Ic., f. 124; A. complexa, 
Hutton, Trans. N.Z. Inst., ., p. 181. Shell oblong, ovate; anterior 
terminal valve radiately eight-ridged ; interstices undately granosely 
striated ; posterior small, retuse ; lateral areas anteriorly decussately 
granosely striated; grains obtuse throughout; ash green, sparingly 
stained with yellow towards the middle; mantle horny, beset with a few 
bristles (Reeve.) 
S. Australia. (Angas.) 
Sub-Family— Cryptoplacine. 
Mantle with a double series of pores beset with horny bristles, or a 
single series of pores furnished with tufts of calcareous spines. 
Genus, PLAXIPHORA—Gray. 
Mantle with a double series of pores beset with bifurcate bristles, 
one row at the insertion of the valves, the other at the external margin ; 
mantle-margin smooth and horny, or more or less covered with setose 
or furfuraceous scales. Shell with the valves broad, transverse, external ; 
the hinder valve small, with the apex posterior, and with a slight notch 
on the hind lower edge, its plate of insertion slightly raised, smooth, 
not divided into lobes at the sides; plates of insertion of the middle 
valves bi-lobate, those of the anterior usually about nine-lobed. 
P. biramosa, Quoy and Gaimard, Voy. Astrolabe, iii., p. 378, 
pl. 14, f. 12-16; TZ: corticata, Hutton, Trans. N.Z. Inst., i., p. 180. Body 
oval, flattish, red, girdled with two series of double bristles ; margin 
hairy ; valves flattish, greenish-red or white, anteriorly transversely 
striated (Q. & G.) 
Wellington. Campbell Island. 
Reeve is quite wrong in uniting this species with C. setiger, King. 
P. terminalis, Sth, Voy. Erebus and Terror, Moll. p. 4, pl. 1, 
jf. 13. Shell elongately-ovate, rather elevated, roundly angled along the 
top of the valves; black or bluish-black, with a white wedge-shaped 
stripe, with a black one within it down the centre of the valves, forming 
a continuous white stripe divided by the black one along the centre of 
the shell ; in some specimens with a few short white dashes diverging 
from the radiating ridges; the intermediate valves mucronated, bisected 
on each side by one raised radiating nb; the posterior margins sinuated 
and thickened by coarse concentric lamelle; the entire surface is 
covered with minute striate-wrinkling, those near the ridge being coarser 
than the rest, and radiating from it like the webs from the shaft of a 
