200 HYALONEMA (HYALONEMA) AGASSIZI. 
Fig. 8. 
establishment of separate varieties. The distinction of different forms within 
the species, designated A, B, C, D, E, and F, is a sufficient division. 
The species composed of these six forms is most closely allied to the Hya- 
lonema (Hyalonema) obtusum and the Hyalonema (Hyalonema) polycaulum. 
The outer appearance of the variety gracilis of H. (H.) obtusum is indeed nearly 
the same as that of form A. These latter differ, however, from H. (H.) obtusum 
in the following respects:— the dermal pinules are considerably longer in both 
varieties of H. (H.) obtusum than in any of the forms described above; the 
