REPORT ON THE TUNICATA. 287 



The direct descendants of such a form arc probably the genera Cynthia and Micro- 

 cosmus, while from this stem two side branches have arisen, one (E.) resulting in the 

 ancestors of the family of the Molgulidse, and the other by the development of a peduncle 

 (8), leading to the Bolteninse, and especially to the genus Boltenia — Culeolus and 

 Fungulus heing comparatively recent modifications (9). 



E. is a modified Cynthiad form, in which the interstigmatic vessels have heeonie curved 

 and probably spirally coiled, so that the branchial sac has the structure found in the 

 typical Molgulidse. The genus Eugyra has probably been formed by the divergence from 

 the mainline, between E. and Molgula, of a form (10) in which the folds in the branchial 

 sac had become rudimentary. 



