C. Spence Bate on the Penwidea. 173 
The ‘ Challenger’ specimen is undoubtedly S. cristata of De 
Haan; but it agrees with Olivier’s description of S. lancifer 
in all points, excepting that Olivier says that the latter has 
five or six teeth posterior to the line of the frontal margin, 
whereas in our specimen, as well asin De Haan’s, there are 
properly only four. But when we consider how general were 
the descriptions given of animals a few years since, and even 
now by some writers, I think it highly probable that Olivier 
reckoned in the number behind the trontal margin the un- 
usual and prominent tooth that projects anteriorly from the 
first somite of the pleon. 
Olivier’s specimen was procured from the Indian seas; 
although the habitat is omitted in the ‘ Histoire des Crustacés,’ 
it is given by Edwards in a note to the species in the ‘ Annales 
des Sciences Naturelles.’ De Haan’s was from Japan ; and the 
‘Challenger’ took it south of New Guinea in about 28 fathoms 
of water. 
Stcyonia levis, n. sp. 
Surface of the animal smooth. Rostrum armed with five 
teeth, dorsal carina with two. Hepatic tooth small. Pleon 
slightly carinated. 'Telson as long as the outer plates of the 
rhipidura. 
This species can only be mistaken for S. parvula of De 
Haan, but differs from it in being more slender, in having 
the rostrum without a tooth on the lower margin, and in 
having the apex terminating in a slender bidentate point. 
Length 1 inch. 
Taken north of New Guinea, at a depth of 150 fathoms of 
water. 
Penzxida. 
The genera in this family are laterally compressed; fur- 
nished with a long rostrum. Gulls dendrobranchiate, branches 
filamentous. Eyes well developed. First pair of antenne 
biramose, furnished with a protarsema on the inner side, and 
a stylocerite on the outer. Mandible having a two-jointed 
synaphipod. First three pairs of pereiopoda subequally chelate. 
Carpus long, &c. 
First pair of pleopoda single-branched, and in the male fur- 
nished with a petasma. 
PENAUS, Fabricius. 
Body compressed. Rostrum carinate. Ophthalmopod bi- 
articulate. First pair of antenne having the dorsal surface 
deeply excavated to receive the eye, and furnished on the inner 
