Sentence:  In the <WSD>jeju</WSD>, the swim bladder has a respiratory function, while in the aruana it is an hydrostatic organ. Both are physostomes, and the swim bladder is divided into 2 chambers whose walls are made up of 3 enveloping membranes or mantles. 
Meaning of the word marked with <WSD> tags:  A South American (Amazonian) erythrinid fish, "Hoplerythrinus unitaeniatus" (formerly sometimes "Erythrinus unitaeniatus").