THE ANNALS 
AND 
MAGAZINE OF NATURAL HISTORY. 
[FIFTH SERIES. } 
No. 45. SEPTEMBER 1881. 
XIX.—On the Penwidea. By C. Spence Bate, F.R.S. &e. 
(A Critical Examination of the typical Specimens of the Penseidee of 
Milne-Edwards, preserved in the Museum of the Jardin des Plantes, and 
a Synopsis of the Species of Penzidea in the ‘Challenger’ Collection.) 
[Plates XI, & XII. ] 
In the collection of Crustacea brought home by the ‘ Chal- 
lenger’ there is a very considerable number of species of 
Peneus and nearly allied genera. Believing these to constitute 
one of the most distinct and natural groups of the class, I have 
endeavoured carefully to determine the various forms that 
distinguish the genera and species of the extremely inter- 
esting tribe Penzeidea. 
The tribe itself differs from all others of the class in the 
structure of the branchie, in having the third pair of pereio- 
poda chelate and in most genera the anterior two pairs also, 
with long carpi and subequally chelate hands; but the pos- 
terior two are never chelate. 
The sexual characters of both male and female are peculiar. 
The first pair of pleopoda is single-branched, the base carrying 
on each side in the former a large curtain-like membrane that 
is attached by a small pedicle near the base of the first joint and 
meets its fellow at the centre, where they are united by a number 
Ann, & Mag. N, Hist. Ser. 5. Vol, viii. 2 
