PLATE XXVIII. 



FIGS. 



1 and 2. Molgula socialis Alder. (p. 56) Test and mantle 

 laid open : three times natural size. 1. Showing 

 outer surface of branchial sac, etc. 2. Showing 

 inner surface, etc. 



3-5. Molgula citrina A. & H. (p. 62) Test and mantle 

 laid open : twice natural size. 3. Showing outer 

 surface of branchial sac, etc. 4. Showing inner 

 surface. 5. Showing digestive and reproductive 

 organs. 



