666 MR. C. SPENCE BATE ON NEW CRUSTACEANS. [Dec. 13, 
PETALOCERUS BICORNIS, 0. S. 
Carapace triangular, anteriorly produced into two horizontal horn- 
like processes; tuberculated with nodulated prominences all over 
the surface, but furnished with a series of large tubercles correspond- 
ing in line with the external margin of the carapace; the antero- 
lateral margin constricted between the branchial and hepatic regions, 
furnished posteriorly to the orbit with two strong, blunt processes, 
and, posteriorly to the central constriction, armed laterally with two 
distant narrow processes, and posteriorly with six closely situated 
large, round tubercles. 
The pleon is nearly symmetrical, being rather larger on the left 
than the right side. Each segment is defined by a marginal promi- 
nence ; that upon the left side is continued from near the middle to 
a process that terminates in a point or tooth at the side, but that on 
the right becomes confluent with a posterior ridge, and forms an irre- 
gular circle, the centre of which is deeply depressed. 
The eyes are small, of a green colour, and surmounted on denti- 
culated peduncles. The first pair of antennze consist of three equal- 
lengthed joints (of which the first is the more robust), together with 
a short, stout, pilose flagellum and a slender secondary appendage. 
The second pair of antennee have a compound scale, consisting of 
two large and two short compressed processes, and the third joint is 
furnished with two or three sharp, strong processes. 
The first pair of pereiopoda are chelate and strong, echinated 
with blunt-pointed spines, and terminate in fingers that are flattened 
at the extremity, and furnished upon the outer surface with numerous 
tufts of hair, that spring from the summits of the numerous tubercles 
that are found there. The second, third, and fourth pairs of pereio- 
poda are more slender than the first, resemble one another very con- 
siderably, and are furnished with short, sharp, and slightly curved 
dactyli. The fifth pair of pereiopoda are rudimentary appendages ; 
they consist of but five joints, the last of which terminates in a blunt 
extremity that is furnished with a considerable brush of hair, and is 
probably used for the purpose of cleansing the branchial appendages. 
The pleopoda are present in the female, with the exception of the 
first pair (which are small) only upon the left side of the pleon, as 
exemplified in our specimen. 
This species differs from White’s P. dellianus in having a horizontal 
bifurcate rostrum to the carapace, being more distinctly tuberculated, 
and in the pereiopoda being more strongly spinated. 
This handsome species is of a yellow colour, picked out with purple 
between the tubercles. 
It was dredged in Esquimalt Harbour, in ten fathoms of water. 
HippoLyTE ESQUIMALTIANA, Di. §. 
Rostrum as long as the carapace, armed with four teeth at the 
base, the posterior being just behind the orbits, and the anterior being 
near the centre of the rostrum, the anterior half of the rostrum 
being straight and smooth. ‘Ihe inferior margin is excavate at the 
