



DJAZONA. 003 



Species of Didemnium 



candidum, Sav. roseum, Sav. 



gelatinosum, Sav. 



Genus DISTOMT7S, Gaertner. 



Test senti-cartilaginous, sessile, polymorphous ; systems 

 numerous, usually circular. Tunicaries arranged in one or 

 more ranks, at unequal distances from a common centre ; 

 anal and branchial orifices regularly and equally six-rayed. 



Syn. Polyzoua, Fleming. 



Ex. D. ruber, Savigny, pi. 135, fig. 4. Individual, D. 

 ruber, fig. 4, a. 



This genus and the following, Diazona, belong to the 

 bi-stellate Didemnians, in which both orifices are rayed ; in 

 the other genera the oral orifice only is rayed. Species are 

 found in Europe, South Africa, and Australia. 



Species of Distomus. 



fuscus, Sav. variolosus, Gaertn. 



ruber, Sav. vitreus, Sav. 



Genus DTAZONA, Savigny. 



Test gelatinous, orbicular, sessile or sub-pedunculate; 

 system single. Tunicaries very prominent, arranged in con- 

 centric circles on an expanded flower-like disc; branchial 

 and anal orifices six-rayed ; abdomen pedunculate. Ovary 

 inclosed in the intestinal loop. 



Ex. D. violacea, Savigny, pi. 135, fig. 5. Individual, 

 D. violacea, fig. 5, a. 



One species only of this genus has been described, from 

 the Mediterranean. 



