FRIEND OR FOE 99 
which in 1876 he named Pachyqrapsus advéna; one was a 
Nautilograpsus (cr Planes) minutus, a species scarcely ever 
found in the Mediterranean ; the remainder belonged to 
two species, which M. Catta speaks of as Plagusia squa- 
mosa and Plaqusia tomentosa. The latter,a South African 
species, should rather, it seems, be designated Plaqusia 
chabrus (Linn.), and the former Plagusia depressa (Ha- 
bricius). It was this last-mentioned one that was the most 
numerous, being present in hundreds. As an Atlantic 
species, it might not have had far to come. The point 
of special interest, however, lies, as Catta explains, in 
showing the effects on distribution that may be produced 
by unconscious human agency. 
Family 4.—Pinnotheride. 
The carapace is usually more or less membranaceous, 
convex or depressed, with the antero-lateral margins entire 
or very slightly dentate. The ‘front,’ orbits, and eye- 
stalks are very small. The buccal frame is usually arcuate 
anteriorly. The third maxillipeds have the fourth joint 
well developed, and usually the third also, the fifth articu- 
lated at the apex, or at the front inner angle, or more 
rarely the front outer angle, of the fourth. The chelipeds 
in the adult male are small or moderately developed. The 
walking legs are slender and generally naked, with the 
seventh joint stiliform, unarmed. The pleon of the male 
in general does not cover the whole width of the sternum 
between the last pair of legs. 
The crabs of this family are small, and many of them 
live in the shells of bivalve molluscs, tests of Echini, tubes 
of annelids, and other borrowed habitations. Miers dis- 
tributes five-and-twenty genera over four sub-families. 
Pinnothéres, atreille (in Bosc), 1802, was known to 
the ancients under the same name, but more commonly 
under the name Pinnotéres. It is a great pity that 
Latreille did not adopt the latter, which is in all pro- 
bability the older form. Small as the difference in sound, 
the difference in sense is considerable. Pinnotheres means 
