40 
to P. marmoreus, for the length of this terminal joint in them is more 
than twice the breadth. 
The colour and disposition of the markings in P. marmoreus are 
different in almost every individual I have seen, and consist of a 
mottling of red and white spots and lines of various sizes and in- 
tensities of colour. In some the white is not pure and bright, and 
yet not sufficiently debased that one could describe it as bluish or 
greenish or yellowish white ; in others it is clear and bright like white 
porcelain. So likewise with the reds: these may be pale brownish, 
bistre, Indian red, or dull crimson; laid on as a network over the 
white, or sprinkled in dots of several sizes and tones. 
In this individual those portions of the carapace covering the 
gastric, the cardiac, and the genital regions are solidly coloured with a 
dull crimson. Seeing how accurately this coloration corresponds 
with the boundaries of these regions, I concluded that some diseased 
condition of the organs beneath had caused the aberration, but on 
taking off the carapace and examining the tissues beneath I could 
find not the slightest indication of any cause for the abnormal condi- 
tion of the exterior. Iam ata loss to explain the variety, but shall 
keep a sharp look-out for further examples of the species, to find out 
if this is a recurring variation. Meanwhile I think it is of sufficient 
interest to be recorded in our “ Proceedings.” 
Whilst on the subject of swimming crabs I may note that a male 
specimen of the beautiful Bathynectes longipes (Risso), or long-legged 
swimming crab, has been recently added to my collection from deep 
water near here. It is a Mediterranean species, of which the first 
recorded British specimen was dredged in Cornish waters by Edward 
Forbes in 1848, and later individuals appear also to have been taken 
west of Plymouth. The entire upper surface and much of the lower 
are uniformly coloured bright brownish red. The carapace is some- 
what boldly sculptured, and its extreme breadth twice the length of 
its depth from front to back. A prominent ridge extends right along 
this longer axis, and ends at each extremity in a long and strong 
spine. The limbs are much longer in proportion to the trunk than 
in any members of the genus /ortuwnws—where this was formerly 
placed; the hinder pair, though flattened for swimming, do not 
indicate that the crab is a surface swimmer, but more probably a 
denizen of the redweed regions at about fifteen fathoms. It is 
curious that this, the only specimen I have yet obtained, should also 
be a singular variety. Normally the antero-lateral margin of the 
carapace 1s five-toothed, of which the long spine previously mentioned 
forms the hindmost of the series. Now in my specimen the first and 
second of these teeth are one, the intervening space being filled up 
in the course of development. 
When an opportunity arises for attending a meeting I hope to 
bring these and other specimens of local Crustacea with me, but I 
am fearful of entrusting them to the tender mercies of the Parcel 
Post officials. 
