! 
176 C. Spence Bate on the Pencidea. 
Specimens in the ‘Challenger’ collection from various 
localities in the Australasian archipelago correspond closely 
with Dana’s description and figure, and, I have no doubt, are 
the same species, but are generally about twice as large. They 
may readily be distinguished from closely approximating forms 
by the petasma on the left ventral side of the male being 
longer than that on the right, and by the form of the ventral 
plates between the coxe of the two posterior pairs of pereio- 
poda of the female (which is too complicated to be followed in 
a verbal description, but which will be illustrated in the 
memoir on the subject in the ‘Challenger’ reports), and two 
long ventral teeth between the second pair of pereiopoda. 
Peneus setiferus, L. (Pl. XI. fig. 1.) 
The specimen of this species in the collection of the Museum 
of the Jardin des Plantes is a male animal, and is the type of 
Milne-Edwards’s description. It has the rostrum as long as 
the scaphocerite, straight and styliform at the extremity, 
and armed with two teeth on the lower and nine or ten on 
the upper margin, which is prolonged posteriorly in the form 
of a slight crest to half the distance between the frontal 
and the posterior margins of the carapace ; and on each side of 
the rostrum a small ridge reaches nearly to the stomachic 
region. There is no little tooth above the ophthalmopod, 
which is long and supports a large eye. The antennal filaments 
are about half the length of the peduncle which carries them. 
The flagellum of the second pair of antenne is excessively long ; 
and there are no spines on the lateral margin of the telson. 
Length about 7 inches. 
It is often found in very considerable numbers at the em- 
bouchures of the rivers of Florida. That in the collection is 
labelled “* Guadaloupe.” 
An examination of this species shows that the outer flagellum 
of the first pair of antenne has the small articuli obliquely 
arranged, and the upper margin of each produced into a sharp 
posteriorly directed tooth. I have not seen this structure in 
any other species, and I believe it is a sexual character only. 
The petasma attached to the first pair of pleopoda is longi- 
tudinally folded as a double tube. 
Telson dorsally grooved longitudinally, and terminating in 
a sharp point; lateral margins without spines, but thickly 
furred with hair. 
Milne-Edwards has grouped this species among those that 
have no groove in the median line between the base of the 
rostrum and the posterior margin of the carapace. This is 
by no means a definite character of specific value, inasmuch 
