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Some British Spider Crabs. 
By Epwarp Step, F.L.S. Read April 22nd, 1897. 
THe Spider Crabs inhabiting British seas number a round dozen, 
and they are characterised bya general resemblance to the Avachnide. 
The ambulatory limbs are more or less cylindrical in shape, the 
joints of pretty equal thickness throughout, and in some species 
drawn out to a length that suggests the ‘‘ harvestman ” among spiders. 
Their bodies, too, are much longer than broad, and somewhat 
triangular in general outline. Another item shared in common by 
all these Spider Crabs is the tendency to develop innumerable 
spines and hooks upon the carapace and other portions of their upper 
surface, and to turn these appendages to the best account. 
Although they possess so much in common which distinguishes 
them from other crabs, these marine “‘ spiders ” differ so much among 
themselves that systematists have arranged them into seven genera 
belonging to three separate families. Their correct relationship, as 
fixed by the authorities for the time being, is as follows : 
Family. Genus. Species. 
( Macropodia. . . . vostratus (L.). 
| 8 Wr et se doneizostris)( Mallore): 
irae J Acheus . . . . . cranchit (Leach). 
ph) nachus "Se ee dorsertens7s (penn): 
| - SE dorynchus (beach): 
Ne SHE i06. unr hined ewan Corina aus (I berveln)y 
(Maia) 1 Te squinade (Elerbst)* 
| pe SN TS REIN otirech clei a We CiteHAgOIS (lbs) 
Manp& Bene) g) i eee nCOaTeLacu oa ecel): 
ees.) Ne em eenre/7aodo7. eerie). 
ey Bina coder tee, 
PARTHENOPIDAD es) i Lurynome "ss" aspera’ (Penn.). 
It is not my intention at present to deal with the whole of this list, 
for the very good reason that I have not an intimate acquaintance 
with them all. With two-thirds of the number I am sufficiently familiar, 
through the medium of living specimens from Gerrans Bay, to justify 
me 1n offering a few remarks. Most of the others are known to occur 
on the Cornish coast, and I am hoping to extend my knowledge to 
several of them during the coming summer. 
I have remarked that they make full use of the liberal array of 
hooks and spines with which Nature has endowed them, and they 
do so by attaching fragments of weed, zoophytes, sponges, ascidians, 
etc. If the females of our own race were similarly endowed with 
