1881. ] Geology and Paleontology. 499 
in all directions with a cork plate (perfectly soft and no grains) 10 
mm. square and moistened with a drop of glycerine. This treat- 
ment produces the relief. Frequent examinations must be made 
under the microscope, to observe the point where the desired 
transparency has been reached (not less thano0.o1 mm.). In some 
cases as for Trichites and Grammites it is best to warm the raw 
plate and saturate it with a mixture of wax and paraffine. When 
terium, Vibrio, Asterothrix, Protoleptis, Zodgleea, etc. 
3. These forms constitute seven generic types (thus far) in a 
lower and higher order. 
A. Naked Plasma, forming indefinitely outlined bodies, without indication of an 
exterior wall. 
I. Racostromide. Plasmatic thalloms, stronger trunks branching into many con- 
nected branchlets. Substance uniform, without celluloid structure, (Color in 
section, brown red to deep purplish red, semi-transparent.) UAE 
LE Trichodide, Trichomic plasma, running into numerous capillary ramifications. 
“eparation of the plasma into two substances indicated. 
III. Grammitoide. Plasmic thalloms composed of a honeycomb web. No cells. 
Uniform opaque substance. : 
IV, Asterophragmide. Plasmatic thalloms resembling Racostromium, but w 
substance is connected with radially arranged spheres, composed of centro- 
V. Blastophr agmide, ‘Trichoid plasma forming Trichomata, from whose granular 
stance polarizing spheres are formed, as in Asterophr: ium. 
B. The plasma forms definitely outlined bodies with an indication of external 
wall, 
VI. Plasmide. The thalloid plasma is not yet clearly outlined by an external bbs 
but is composed of a granular, or fibrillary substance from which primary ceils 
ed, ; 
occide. The plasmatic body has become a cell, surrounded by an ex- 
ternal wall not fully developed 
Of these types, fifty-two specific forms are described in the 
