BRITISH STALK-EYED CRUSTACEA. 457 
Aantho rivulosa, M.-Edwards. 
Leach appears to have considered this species a variety of the 
last-named, though its specific characters seem well marked. Its 
size is, on the average, smaller than that of X. florida; its carapace 
is very level, whilst that of the other species is convex. The 
colour of this crab is very variable, and specimens are often 
beautifully marked. It is usually of a yellowish tint, variegated 
with red, some specimens, however, are nearly white, and others 
possess markings more definite and more numerous. Another 
marked distinction is the groove with which the movable pincer 
is furnished, and the pincers themselves are brown, whilst those 
of X. florida are black. 
Bell thinks that there is no doubt that this is the Cancer 
hydrophilus of Herbst; he also mentions it as being referred to by 
Mr. Couch, of Polperro, as more common at that place than 
X. florida. It would be interesting to know if this abundance 
has been confirmed. Its general habits and locality are similar 
to those of the last-mentioned species, and we should therefore 
suggest that where X. florida occurs diligent search should be 
made for the rarer and more remarkable form, X. rivulosa. We 
found this species not uncommonly at very low tide, with X. florida, 
under rocks below St. Michael’s Mount, Cornwall. We have 
received it sparingly from under stones near Lynton, North 
Devon, and a single specimen from Milford Haven. It has 
been also recorded from the Shetlands, Hebrides, South Devon, 
Valentia, and Galway; rare in the two latter localities. 
We have taken it with ova at the same time as X. florida, and 
probably it sheds its young at about the same period. 
Xantho tuberculata, Couch. 
Bell, in the Appendix to his work, mentions, and in fact 
describes, this species, but we have not yet met with it ourselves, 
and very little appears to be known about it. If it is a well- 
- defined species, no doubt it is limited to extreme localities, which 
may thus account for its recent non-occurrence. Itis described as 
_ partaking of the characteristics of both of the former species, the 
hands and wrists being somewhat tuberculated and rugose. The 
whole of the ambulatory feet having the fourth, fifth and sixth 
3.N 
