VESICULARIAD^E. 



21 



together on the branches ; animals with eight ten- 

 tacles and a gizzard. 



M. gracilis. Fig. 36 ; n. s. and mag. 



Avenella (Dalyell). Slender, thread-like, creep- 

 ing, nearly simple ; cells large, solitary, irregularly 

 scattered, set in a single row, slightly contracted at 

 the top, curved ; animals with from twenty to 

 twenty- four tentacles, and a small gizzard. 



A. Dalyellii. Fig. 37 ; mag. 



Nolella (Gosse). Cells erect, sub -cylindrical, 

 crowded on tubes which form an undefined encrust- 



38 



ing mat ; animals with eighteen tentacles, forming 

 a bell. 



N. stipata. Fig. 38 ; n. s. and mag. 



Bowerbankia (Farre). Matted and creeping, 

 or erect and irregularly branched ; cells tubular, 

 densely clustered ; animals with eight to ten ten- 

 tacles, and a strong gizzard. 



B. imbricata. Fig. 39 ; n. s. and mag. 



