PIERCED SHELLS AND CHITONS 269 
with the last two, so that by Pilsbry it is consid- 
ered to be only a sub-species. 
Mopdlia ciliata, Sby., the Hairy Chiton, has been 
sadly confused with other species. It is brighter 
colored than M. muscosa. The girdle is wide, yel- 
low or brown, somewhat clothed with curling, 
strap-like brown hairs, which bear near their bases 
4 bunch of minute, white, acute spines. Var. wos- 
nessénskii, Midd., has a shell elongated, the back 
roundly arched; color, olive to drab; sculpture, 
faint. It has been found at Sitka and Olympia. 
The main species extends along the coast from the 
far north to Monterey. 
Placiphorélla velata, Cpr., the 
Veiled Chiton, Figure 301. This 
singular species is more nearly 
eireular than any of its relatives 
on this coast. At the anterior end 
the mantle projects considerably, 
forming a distinct veil, which is 
set with scattering hairs. The 
Fig. 301 valves are low arched, of a dull 
reddish color without, but whitish within. Length, 
30 to 50mm. It is found from Humboldt Bay south- 
ward. 
Katherina tunicata, Sby., the Black 
Chiton, Figure 302, was named in 
honor of Lady Katherine Douglass, 
who first sent a specimen to the Brit- 
ish Museum. The shell is oblong, ele- 
vated, the valves mainly covered by 
the black, leathery girdle. This singu- 
lar arrangement of the parts 1s so 
striking that it cannot be mistaken for Fis: 30% *2 
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