33 
concealed by a mass of these marine plants growing upon their 
surface, where their roots find a firm hold amongst the villous coat 
of ‘the shell and limbs. ‘This is especially the case with the females, 
which in this as in many other species are less active than the males.” 
And in a foot-note he adds, “Say supposes that the fwci which 
are found covering certain Crustacea are merely entangled mechani- 
cally in the hooked hairs by which they are covered ; but there is no 
doubt they actually grow upon them, and are attached by roots. 
This is evident from the healthy state of the plants, as well as from 
the direction of their branches.” 
Such a statement is absolutely startling, coming from Bell, who 
professes to know the living crab, for it makes clear the fact that 
his descriptions were not made from the life, but from cabinet 
specimens ; also that he was ignorant of marine botany. Through- 
out his descriptions he never again mentions these hooked hairs, 
which are such an important feature of their natural outfit, although 
he does see and mention the clubbed hairs of Psa. No naturalist 
with Say’s theory before him could make a careful examination of 
the living crabs without coming to the conclusion that Say was right, 
and it is very clear that /wcz could not be attached by roots, for 
they have none. Nor does the direction of the branches support 
Bell’s contention as he declares, for it is the nature of marine plants 
as of terrestrial vegetation to grow up towards the light ; but these 
fragments on the crab’s surface take a more or less horizontal direction. 
But, in truth, a very cursory examination is sufficient to show any one 
that these weeds have no natural attachment to the crab, and that 
they are simply caught under the hooked hairs or glued to the 
straight ones. Nor do these slim-legged spider-crabs affect ud ; 
they prefer the more delicate Chlorophyceze and Rhodophycez. 
The only weeds I have found growing zaturally upon them are 
those of a low confervoid nature that grow rapidly over any sub- 
marine surface. Zaza sqguinado, however, does use Fuci. 
The specimens of animal life to be found upon AZacropodia 
rostratus are not numerous, but there is no room for doubt as to the 
reality of the vital attachment of these. One of the tubeworms 
(Serpula) is frequently conspicuous on the carapace, and some form 
of Zoantharian ; occasionally also a small saddle oyster (Axomia) ; 
otherwise there is little animal life to be found there. 
In order to bring out some of the details of structure more clearly, 
I have mounted on one card fragmentary portions of JZ. rostratus. 
From these disjointed parts will be gathered at a glance certain facts : 
—(a) the remarkable difference in the development of the abdomen 
in the two sexes, its greater breadth and convexity in the female 
being due to the fact that it has to serve as a pouch to protect a great 
mass of ova. And here I might mention the fact that the females of 
this species are sexually mature quite early in life, for they bear eggs 
when they have not reached one-fourth of their full size; (0) the 
rostrum is much longer in the male than in the female, and the che/e 
3 
