ANCEUS, 17k 
dique, Crustaces,” pl. 329, fig. 24, and described in the 
text as “ Crustace du genre Praniza du Docteur Leach.” 
In the seventh volume of the ‘‘ Transactions of the 
Linnean Society,” Col. Montagu published the descrip- 
tion and figure of an animal under the name of Cancer 
maxillaris, which proves to be the male of this genus; 
and in the ninth volume of the same work, he also pub- 
lished a figure and description of a female, under the 
name of Oniscus ceruleatus.* 
In “ The Edinburgh Encyclopedia,” vol. 7, Dr. Leach, 
in adopting the Latreillian principles of classification to 
the Crustacea, proposed the generic name of Gnathia for 
the Cancer mazillaris. He had previously, as above stated, 
proposed the MS. name of Praniza for the female. 
In “ Hist. Nat. des Crust. de Nice,” 1816, p. 52, pl. 2, 
fig. 10, Risso subsequently described the male of a Medi- 
terranean species under the name of Anceus forficularis. 
In the fifth volume of ‘‘ Loudon’s Magazine of Na- 
tural History,” the late Dr. Johnston published some 
observations on the genus Praniza, and added the descrip- 
tion and figure of a second species, Praniza fuscata, 
observing that these animals, by means of their legs, 
are able to creep on the bottom of the sea, which they 
do slowly, but they swim with greater rapidity, pro- 
pelling themselves forward by the quick motions of the 
series of ciliated fins placed beneath the tail. 
The remarkable structure of what is supposed to be 
the respiratory apparatus of these animals (intermediate 
as it is between that of the typical Amphipoda—namely, 
a series of free appendages—and that of the typical 
Isopoda—in which the appendages are enclosed by a 
bivalve operculum), induced Professor Westwood to com- 
* This figure was also copied in the Encyclopédie Méthodique, pl. 336, fig. 
28, but under the erroneous name of Oniscus ( Celino) thoracicus of Montagu. 
