DUBIOUS DOMICILES 169 
the friction of its body, but Aurivillius shows that there 
is a secretion from glands in the sides of the carapace 
adapted for the purpose, and that the joints in the fourth 
and fifth pairs of legs of Hupaqurus are nicely arranged to 
assist in distributing the secretion. 
Paguropsis, Henderson, 1888, is regarded as holding a 
unique position among Hermit-crabs, inasmuch as the last 
two pairs of legs of the trunk are subdorsally placed, and 
the unpaired appendages of the pleon are on the right side 
instead of the left. Dr. Henderson observes that ‘among 
the Pagurids generally, the soft abdomen, as a result of 
its being thrust into a Gastropod shell, the spiral of which 
is normally right-handed, has assumed a similar curve, and 
the original right side thus closely applied to the columella 
loses its appendages.’ The two specimens taken at a depth 
of about a hundred fathoms off Tables Island, were free, but 
the character of the pleon makes it probable that it was ~ 
protected in some way. ‘The position of the appendages 
on the right side might be explained as adapted to some 
species of Gastropod with a left-handed spiral, but the fact 
that the pleon is simply bent on itself points to some other 
kind of dwelling. 
Pylochéles, A. Milne-Edwards, 1880, has the carapace 
completely calcified, the chelipeds equal, the pleon sym- 
metrical and well developed with broad semi-calcareous 
terga and paired appendages of one kind or another on the 
first six segments, those of the sixth segment forming with 
the telson a powerful swimming fin. This remarkable 
genus is said to form a connecting link between the Pagu- 
ride and Thalassinide. The type species, Pylocheles 
Agassizii, A. Milne-Edwards, was dredged by the Flake 
from a depth of 200 fathoms off Barbados, and found in 
the hollow of a piece of sandstone, the mouth of which was 
closed by its claws, as the mouth of a shell is by those of 
of an ordinary hermit. Pylocheles spinosus, Henderson, 
which is depicted on Plate VII., is Australian. Nothing 
is known about its mode of lodging itself. For this genus 
Mr. Spence Bate in 1888 established the family Pyloche- 
lide, which he placed between the Galatheide and Thalas- 
