714 
before as peculiar to the Mediterranean, was found 
-extending from the coasts of Morocco to the Azores 
and the Canaries. But the most noticeable example 
of great geographical distribution is presented by 
Lithodes. These animals have hitherto been noticed 
only at the surface, in the waters of the poles. We 
found them at the tropics. But here, to meet the 
changed conditions of their surroundings, they have 
deserted their former depth for one of a thousand 
metres. This fact is important as bearing on the 
animal distribution of the oceans. It shows, first, 
that certain animal forms extend from northern seas 
SCIENCE. 
[Vou. IIL, No. 71. 
colony formed by beautiful Epizoanthi. ‘These Zoan- 
thi originally developed in a shell which has been 
gradually re-absorbed ; and it is the cavity correspond- 
ing to this which this peculiar species of hermit-crab. 
now occupies. 
Galatheans have been found abundant at all zones; 
and the color of the body, generally reddish, becomes 
white with those living at great depths. Certain 
species establish themselves as lodgers in the interior 
of those beautiful sponges, the Aphrocallistes, whose 
tissue resembles lace. Galathodes Antonii, a new 
species, a specimen of which was taken below four 
Fic. 2.— PTYCHOGASTER FORMOSUS, DREDGED FROM A DEPTH OF 950 METRES. (NATURAL SIZE.) 
to the tropics; and, next, that animals from the poles 
have only to seek deeper water in proportion as they 
approach the warmer regions, to reach a zone suited 
to their organization. 
The Paguri, commonly called hermit-crabs, have 
been found at five thousand metres. The bodies of 
these animals are protected only at the head and 
thorax; and, to shield their abdomens, they lodge in 
shells whose size corresponds to their own. But, as 
the shells of deep water are always very small, the 
abyssal Paguri obtain only very imperfect protection. 
One of these species, obtained on the Morocco coast 
and in the Sargasso, presents a very singular habitat. 
It lodges, not in a shell, but in a regular animal 
thousand metres, is here figured (fig. 1). Ptychogaster 
formosus (fig. 2) is interesting on account of the posi- 
tion of its abdomen, folded twice upon itself. 
The group of the Eryonides is represented by a. 
number of species and genera. Polycheles and Wil- 
lemoesia, whose tissues are so transparent that the 
stomach is visible through them, were taken at four 
and five thousand metres. The species of Penta- 
cheles, common between one and two thousand 
metres, present forms very similar to those described 
in the fossil state, under the name of Eryon. At the 
exhibition of the Talisman collection, there is placed 
beside Pentacheles crucifer a calcareous plate com- 
ing from the Jurassic deposits of Solenhofen in 
eS a 
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