PLATE XVIII
1. A rough spongelike- looking ball with strong spines .
2. Spongolithus (?) a spicule.
3. A state of Haliomma a strong spokes from central nucleus to circumference, at unequal distances some network apparently spinning partly over one side , according to Müller's description.
4. Spongolithis anchora of Ehrenberg . A spicule.
5. Spongolithis Ramosa Ehr.
6. Serpent-like form very frequent and variable in the Barbados deposit.
7. Lithasteriscus reniformis . Ehr., " Nord and Sud Amerika," Taf. VI, fig. 35. I think all these bean-like forms are warted or roughened on the surface, not truly foraminated.
8. An irregular three-lobed transparent Plate from Chimborazo, Barbados, analagous to fig. 6 on Pl. VII. Dr. Wallich says these are parts of an Organism constituting a new Genus intermediate between Sponges and Polycystins; this plate, forming part of the outer siliceous skeleton, the interior being filled with free spicules . The ovals, Nos. 1 and 2 , on Pl . 7, (of which many more examples have since been found) are plates instead of spicules, taking the place of an internal skeleton of a kind of Organism of which no perfect specimen has yet been found ; and which is also intermediate between Sponges and Polycystins.
9. Spongolithis Aspera.
