r 
a depth of ca. 20 fathoms. It is covered with broken shells, coral 
pieces and Lithothamnia's in such a way that it is simply impos- 
sible, when seeing it from above, to discern that it is a living 
animal. The figure can only give an imperfect idea of this 
wonderful case of protection. 
I would still mention as 
a possible case of protective 
resemblance Acanthochiton 
(Fig. 6). It resembles to a 
very striking degree the sea- 
urchin Echinometra oblon- 
ga, which is found in simi- 
lar localities. . Still this may 
aS well have nothing at all 
with Mimicry to do. The 
Spines of this Chiton are in 
themselves a good protection 
and do not become better for 
the resemblance with Echi- 
nometra. When the Chiton 
rolls itself up on being re- 
moved from the rock, it strik- 
g $ Fig. 6. Acanthochiton sp. The specimen has been 
Ingly resembles some spiny slightly damaged in one end. Nat. size. 
fruit — but I do not think 
either, that this has anything with mimicry to do. The Chitons 
have not the habit of rolling themselves up except when removed 
from their place — but then they are not liable to be taken for 
an inedible fruit. — Still I have thought it worth while men- 
tioning this peculiar Chiton. 
IN Tanicates. 
Ås might be expected of animals like the Tunicates there is 
hardly anything of protective adaptation in-this group. Only the in- 
vestment of shell fragments and the like in the Molgulids and some 
other forms is a case of adventitious protection as good as any. 
Ha KER STRE) quotes the black Phallusia fumigata, living on 
; Seeliger & Hartmeyer. Tunicata, in Bronn. Klassen u. Ordnun- 
gen. 3. Bd. Suppl. 1893—1911. p. 1731—2 
