58 
instances, when dredging and collecting in tropical seas — there 
is no reason to enter on a description thereof on this occasion. 
Then, perhaps, protective coloration or protective habits are 
upon the whole not so common among marine as among terrestrial 
animals. H.L. Osborn!) has expressed this opinion in the fol- 
lowing passage, with which I agree completely: ,,lt is a curious 
fact, that, while among the terrestrial animals the number of known 
cases of protective mimicry is very large, "among aquatic animals 
it is very small. I have no doubt that the comparative poverty of 
our knowledge of the habits and situation of aquatic animals in part 
accounts for this, but I believe also that there is really vastly less 
mimicking. I do not know of any marine species, that, harmless 
in themselves, mimic formidable species for protection; but there 
are instances in which forms are modified in color or shape so as to 
resemble the surroundings in which they live, and thus escape the 
observation of their enemies.” I must, however, remark that, speak- 
ing of the comparative rarity of protective resemblance in marine 
animals, this should not be applied to the above mentioned special 
fauna's or communities, the Sargasso-fauna etc., because within these 
special fauna's the protective coloration or other adaptation applies 
to the great majority of the animals. 
Furthermore I would venture to suggest that perhaps not all the 
cases that have been recorded as instances of protective coloration 
or protective resemblance, are really to be thus interpreted. When 
Plateau”) mentions as instances of protective resemblance pelagic 
animals like Janthina, Sapphirina, Velella?), Porpita ,,d'un bleu 
plus ou moins pur. et qui, nageant dans les eaux bleues, se dis- 
tinguent å peine du milieu ambiant", I would, on the contrary, 
maintain that I have always noticed them as being very conspicuous, 
SepeSany, Perhaps, the wonderful Sapphirina, which sparkles like 
i ” Mimicry among marine Mollusca. Science. VI. 1885. 
9. 
) F.Plateau: La ressemblance protectrice dans le dytte animal. Bull. 
de PAcad. R. d. sci. de Belgique. 3. Sér. 23. 1892. p. 100 
1892. p. 123) remarks on account of 
observed off the South Coast of Spain, 
”T] 
WwW 
før 
mp 
" 
[ør 
Ft] 
Sa 4 
=. é 
3 
må 
[æj 
gå 
z 
m 
me 
o 
3 
: I can assure that it is just as conspicuous in 
midocean as in the shallow water near the coast. 
