8 CRUSTACEA. 



racic feet ; a condition closely analogous to that of the Cyclopacea and 

 other species among the Edriophthalmia, in which the same thoracic 

 feet are wanting, as well as the abdominal feet, and also the branchiae. 

 Thus it is that the Podophthalmia naturally include two groups, a 

 higher, with the branchiae enclosed in the normal condition beneath 

 the carapax, and a second, or lower, with the branchiae exposed, or 

 wanting. These subdivisions of the Podophthalmia are : 



Order I. EUBRANCHIATA or DEC APOD A. 



Order II. ANOMOBRANCHIATA. 



Eubranchiata. The Eubranchiates or Decapoda are naturally 

 divided by Milne Edwards into the three groups * 



Tribe I. BRACHYURA. 



Tribe II. ANOMOURA. 



Tribe III. MACROURA. 



The nature and propriety of this arrangement will be the subject 

 of extended remark on a future page, where the Eubranchiata come 

 under consideration. 



Anomobranchiata. In the Anomobranchiates the feet are in part 

 two-branched or bifid, and this is an additional mark of their relation 

 to immature forms. But this character is not universal ; and, more- 

 over, it is presented by some species of the first division. We there- 

 fore have not used the term Schizopoda for the group, but give it to a 

 subdivision of the group which is characterized eminently by two- 

 branched feet ; while another small subdivision or tribe, closely allied 

 in most particulars, but with simple feet (Genus Lucifer), forms the 

 tribe Aploopoda* Another portion of these species have the anterior 

 thoracic feet clustered about the mouth, and cheliform, and this cha- 

 racter suggested to Latreille the name Stomapoda (more properly 

 Stomatopoda). This structure has a resemblance to that found in 

 some Macroura, especially the Thalassinidea, and is a proper charac- 

 teristic for one of the subdivisions of the Anomobranchiata. 



The Anomobranchiata will thus include three tribes : 



Tribe I. STOMAPODA. 



Tribe II. SCHIZOPODA. 



Tribe III. APLOOPODA. 



II. EDRIOPHTHALMIA. The Edriophthalmia embrace a great variety of 

 forms and structures, with very unlike habits. Separating the Amphi- 



* From ocrXoos, simple or undivided, and tfouj, foot. 



