508 



TUNICATA. 



together like the spokes of a wheel. Such an arrangement is charac- 

 teristic of the genus Cyclosalpa. 



This union between the individuals of the Salpa-chain must be 

 regarded as colony-formation. Whereas, in the composite Ascidians 

 and in Pyrosoma, the individuals which arise through budding remain 

 connected by means of a common cellulose mantle, connection here 

 takes place through special connecting organs.* This connection is. 



es 



FIG. 277. Diagram illustrating the interconnection existing between the individuals 

 of a Salpa-chain. A, the chain seen from above; B, lateral view, es, endostyle ; 

 em, embryo ; g, ganglion ; h, lateral connecting processes ; h, ventral processes ;, 

 i, branchial aperture. 



not very close. When the fully developed chain passes out from the 

 cavity in the cellulose mantle of the parent and separates from the 

 proliferating stolon, it very easily breaks up into smaller portions ; 

 individuals even become detached from the chain and continue their 

 existence independently. 



C. Development of the Organs in the Bud. 



In the above account of the relation of the buds to the stolon we 

 have in all points followed the short but important description given 

 by BROOKS (No. 92). The most important investigations made in 



* See LEUCKART'S description, No. 28. 



