522 
SUPPLEMENT 
only by the absence of mandibles and palpi, but still further 
by the shorter proportions of the body and the feet. The feet 
appear to have an articulation less than in the other pycno- 
gonides. The last but one appears to form, in the pycnogona, 
only a small inferior knot, and joining the last articulation of 
the tarsus with the preceding. 
But a single species appears as yet to be known, the 
P. b alee 7i arum , figured by Briinniche, Muller, and some other 
naturalists. It is found under the stones on the shores of the 
European ocean ; it is rare on the coasts of England and 
France. 
The genus Phoxichilus M. Latreille at first thought to 
differ from the preceding, in having mandibles, and from the 
succeeding {Nympli on), by these organs being terminated by a 
single digit, and by the want of palpi as in the former genus. 
But having subsequently examined, with more attention, the 
mandibles of the species in which he had established this new 
generic section, he observed that they terminated in a didac- 
tylous forceps, in the same manner as those of the nymph ons, 
and that the inferior digit, covered by the ordure which at first 
had prevented him from perceiving it, was only smaller than 
the superior one, or that which is mobile. But the Phoxichili 
are, nevertheless, strongly distinguished from the nymphons, 
by the absence of palpi. They are also removed from them 
in other points of view — 1. The tube, or siphon, forming the 
sucker, and the aperture of which represents a trefoil, as is 
the case with that of the same part in other animals of this 
family, is bellied in the middle, a little narrowed afterwards, 
and is terminated by a rounded expansion furnished with 
hairs. Each of its sides, and the middle of its back, presents 
two impressed longitudinal lines, and which, uniting by their 
extremities, describe a sort of ellipsis. In considering these 
lines as sutures of united pieces, this tube would be composed 
of six valvules, or laminae, cemented together, and which 
