C. Spence Bate on the Pencidea. 171 
the ‘ Proceedings of the Zoological Society of London,’ March 
5, 1878. Icame to the conclusion that it was desirable to 
see the typical specimens on which Prof. Milne-Kdwards 
determined the forms that he published originally in his 
‘ Histoire Naturelle des Crustacés,’ vol. 11. pp. 403-430. 
In the collection of the Jardin des Plantes, with the coope- 
ration and assistance of Prof. Alphonse Milne-Edwards, I 
was enabled to identify all the old types still preserved in the 
Museum except Penceus styliferus, which, I fear, has got 
mingled with others or the label lost in the hasty removal of 
the specimens to some underground cellars during the unhappy 
period of the Communistic ascendency in Paris. 
It is at the suggestion of Prof. A. Milne-Edwards that this 
memoir is written; and my intention is to adhere as nearly as 
possible to the text of the ‘ Histoire des Crustacés,’ making 
such further additions as appear to me to be necessary for 
the ready identification of the species, together with figures 
Pe such as have not already been published of the typical 
orms. 
The tribe Peneidea contains several genera; but of those 
tabulated in the ‘ Histoire des Crustacés’ certainly Stenopus, 
Oplophorus, Ephyrus, and Pasiphea must be excluded. 
SICYONIIDA. 
Sicyonia, Kdw. Branchie dendrobranchiate, but arranged in 
plates. Scaphocerite angular. 
PENZIDA. 
Peneus (Fabricius), in which the first pair of antenne: are 
shorter than the carapace. 
Penceopsis (A. Milne-Hdwards), in which they are longer. 
Solenocera (Lucas), in which they are longer and have one of 
the rami flattened and concave longitudinally. 
Haliporus, n. gen. Body more slender. 
Hemipencus, n. gen. Rostrum straight, short; five podo- 
branchize present. 
Aristeus, Duvernoy. Rostrum long ; five podobranchie. 
Hepomadus, n. gen. Damaged ; four podobranchie. 
Benthesicymus, n. gen. Rostrum short and cyrest-like; five 
___ podobranchiee. 
Gennadas, n. gen. Like last, with less arborescent branchie. 
Euphema, Edwards. Young Peneid. 
SERGESTID A‘. 
Sergestes, Kdw. First pair of pereiopoda not chelate, second 
and third chelate, fourth and fifth not chelate. 
i 
