ON ZOEA, &;c. 11 



service of the mouth, the former projecting laterally, 

 while the latter are carried in a forward direction, and 

 nearly concealed beneath the body of the animal. 



Tlie apparatus of the Mouth consists of a pair of strongly 

 toothed mandibles, furnished with the rudiment of a palp, 

 and of two pair of jaws, (maxillae) together with an upper 

 and under lip : the maxillse are lobed and spinous, with 

 an external articulated appendage, the innermost of them 

 furnished with a broad ciliated scale at its base, serving 

 it is presumed to fan or aliment the respiratory organ ; the 

 labrum or upper lip, is semicircular and simple, the under 

 lip bilobate and bearded.* 



Independent of the knowledge we notu possess of these 

 animals, we should from the foregoing detail, refer them 

 without hesitation, as Dr. Leach has done, to the Shizopoda, 

 or cleft-footed Malacostraca, and consequently next to Ne- 

 balia, which is also most probably a crustaceous animal in 

 its progress to a more perfect state ; in which case, the only 

 true Shizopodae as yet described, are the animals of the 

 Genus Mysis or Opossum Shrimp, the structure and na- 

 tural history of which, are detailed in the following 

 Memoir. 



* The French have adopted the term Zoe for these atiiinals, whicli, as more 

 simple, and better suited to the genius of our own language than the Latin, 

 may be jjsed in familiar discourse without any impropriety. 



