TUNICA.TA: SALPS 



FIG. 657. 



431 



Biphora or Salp. 

 Salpa maxima, Forskahl. The flat bands are muscular tissue. 



Some kinds of tunicates, as the Pyrosomcs or Pyroso- 

 midse whieli live in cylinder-shaped compound commu- 

 nities are remarkable for their phosphorescence at night, 

 sometimes resembling "incandescent cylinders of iron." 



Dr. Gill, in the paper already cited, recognizes four Or- 

 ders of the Tunicata : 



1. SACCOBRANCHIA, as Ascidium, Boltenia, UlaveUina,Botryttu.8, 



etc. 



2. DACTYLOBRANCHIA, as Pyrowma. 



3. TvENIOBRANCHIA, as Salpn, etc. 



J-. LARVIALIA, as Appendiculaiia. 



