ANCEUS. 171 



dique, Crustaces," pi. 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 

 mnxillaris, 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 caruleatus.* 



In " The Edinburgh Encyclopaedia," vol. 7, Dr. Leach, 

 in adopting the Latreillian principles of classification to 

 the Crustacea, proposed the generic name of Gnathia for 

 the Cancer maxillaris. 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, pi. 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 Encyclopedie Methodiqiie, pi. 336, fig. 

 28, but under the erroneous name of Oniscus (Cctlino) thoracicus oi Montagu. 



