# 82 Rhodora [May 
them with authentic specimens of the latter. The Bermuda plant 
grows always in sheltered places, and is rarely found floating even 
after severe storms; S. lendigerum, a very different species, inhabits ex- 
posed shores, and as already noted, is frequently mixed with S. natans 
after storms. In my last trip to Bermuda I collected a considerable 
quantity of each of the four species spoken of above, and attempted 
to rough-dry it for later study and mounting, but owing to unfavorable 
weather during the last few days of my stay, I had to pack up quite 
an amount still moist. It was more than ten days before it was un- 
packed, and I found that while the three other species were in good 
condition, all of the linifolium form was decayed and worthless. How 
much weight should be given to these considerations as against the 
origin of S. natans from this species it is hard to say; it may be that 
the pelagic condition is sufficient to account for the differences. 
In considering the question of the antiquity of this pelagic form, it 
is interesting to note that at present a considerable fauna is associ- 
ated with the Sargasso Sea, quite distinct from that found on attached 
Sargassum. I have seen statements that at least fifty species of ani- 
mals have been recorded as characteristic of it, many of them seldom 
found elsewhere. This association is so well known to the collectors 
at the Wood’s Hole Biological Laboratory, that when the gulfweed is 
reported as coming near land, they go out to obtain from it a number 
of species that they keep in stock, but never find otherwise. . Among 
these are the attached mollusk, Litiopa bombix, some free amphipods, 
two crabs, Planes minutus and Partunus Sayi, and most interesting 
of all, the fish Pterophryne histrio. It seems to me that the specializ- 
ation of this fish to its habitat in the Sargassum is a strong evidence of 
the antiquity of the latter in its present condition. The markings on 
the fish closely simulate the leaves of the plant, and it has several out- 
growths, exactly like battered and bristly stalks of the plant, and 
except for protection by resemblance, of no use that we can see to the 
fish. It is practically impossible to distinguish the fish from the 
floating alga in which it lives. “The marvellous and undoubtedly 
protective coloration and configuration of this fish render it one of the 
most striking objects which appear on the coast.’”! 
The animals mentioned are displayed in the public collections of the 
Boston Society of Natural History as “Sargassum Crabs” etc. There 
'F, B. Sumner in A biological survey of the waters of Woods Hole and vicinity. Bull, 
Bureau Fisheries, Vol. XX XI, part 2, p. 774, 1913, 
