Explanation of Plate 3 



Fig. 18 — Raistrickia; 18a, equatorial (transverse) plan ; i5&, axial (longitudinal) plan . . p. 55 



19 — Lycospora; 19a, equatorial (transverse) plan; i9&, axial (longitudinal) plan . . p. 54 



20 — Triquitrites ; 20a, axial (longitudinal) plan; 20^, equatorial (transverse) plan . . p. 46 



21 — Cirratriradites ; 21a, axial (longitudinal) plan; 2i&, equatorial (transverse) plan . p. 43 



22 — Calamospora; 22a, equatorial (transverse) plan; 22b, axial (longitudinal) plan . . p. 49 



(Below) 



Graphic comparison of approximate size range of fossils included in the various genera. Dimen- 

 sions are indicated in logarithmic coordination. 



[72 



