50 Mr. W. V. Guise on a new species of Alpheus. 
prize, being a Mediterranean species of the greatest rarity in our 
seas; but upon comparing it carefully with the descriptions of 
Milne-Edwards in his ‘ Histoire Naturelie des Crustacés,’ I be- 
came convinced that I had had the good fortune to obtain an 
entirely new species of Alpheus ; and further investigations have 
only tended to confirm me in that opinion. 
The genus “ Alpheus” is thus characterized by Milne- 
Edwards :— 
Carapace prolonged in form of a hood or vault over the eyes. 
Rostrum small, and sometimes wanting. 
Superior antenne small ; first articulation short, and armed with- 
out with a plate, generally spiniform ; two following joints cy- 
lindrical, having two terminal threads, of which the superior 
is thicker and shorter than the inferior, and presenting traces 
of a division into two filaments towards the end. 
Inferior antenne inserted without and below the preceding. 
Lamellar palp of moderate size, sometimes small and pointed. 
Mandibles provided with a short, broad, palpiform appendage. 
External pedipalps more or less slender and elongated, termina- 
tion broad and somewhat foliaceous. 
Two first pairs of legs didactyle, the first pair strong; the one 
much larger and more robust than the other. 
Second pair weak and filiform, having the wrist multi-articulate. 
Three last pairs of legs monodactyle and of moderate length. 
This genus, says M. Edwards, appears to belong properly to 
the seas of warm climates. Some species are found in the 
Mediterranean ; but the greater part come from the seas of the 
Antilles or from the Indian Ocean. 
The genus is divided into those which have, and those which 
have not, a spiniform rostrum. It is further subdivided into those 
having a spine attached externally to the basal joint of the 
external antenna, and those not so furnished. 
The example now before us will be found to belong to the 
second subdivision of the first division, 7. e. to those provided 
with a pointed beak, and not having an external spine at the 
base of the external antennz. 
Under this head three species are described hy M. Edwards as 
inhabiting the European seas, viz.— 
Alpheus ruber, Alpheus Edwardsii, and Alpheus dentipes, which 
are characterized as follows :— 
Alpheus ruber. “ Body very slender ; larger hand provided with 
four longitudinal carine, two on the upper edge, two on the 
