608 salpidjE. 



In our list of species we have followed M. Krohn in 

 using the oldest name and making it comprehend the two 

 dissimilar states, which had been previously considered dis- 

 tinct species. M. Krohn makes three types, to which all 

 the variations of the associated Sa/jJce are reducible. The 

 first is characterized by the vertical position of the animals 

 forming the chain, the axes of their bodies crossing the 

 axis of the chain at a right angle. In the second the 

 bodies of the individuals are more or less inclined to the 

 axis of the chain. The third group is distinguished by the 

 horizontal position of the component animals, the axes of 

 their bodies being more or less parallel to the axis of the 

 chain. 



Species of Salpa. 



Africana, Forsk. proboscidalis, Lesson. 



democratica, Forsk. punctata, Forsk. 



gibba, Bosc. runcinata, Chamisso. 



polycratica, Forsk. strurnosa, Banks. 



Genus DOLIOLUM, Quoy and Gaimard. 



Body transparent, cask-shaped, open at each end; an- 

 terior aperture somewhat tubular, the margin denticulated ; 

 posterior aperture also produced, its margin ciliated ; 

 muscular bands equidistant ; respiratory cavity wide, 

 central ; gills in the form of two bands stretching across 

 the cavity ; mouth on the dorsal side in front of the 

 fourth band. 



Syn. Anchina^a, Eschscholtz. 



Ex. J), dcnliculatum, Quoy and Gaimard, pi. 136, 

 fig. 4. 



