﻿PLATE I. 



All the figures, unless otherwise designated, are enlarged to 18 diameters. 



PAGE. 



Fig. 1. Rhombopora lepidodendroidea, Meek. A tangential section of 



this species, 27 



la. A longitudinal section, passing a little to one side of the center. 



16. A transverse section. 

 Fig. 2. Rhombopora crassa, n. sp. A tangential section of this species, 

 showing a small macula of spiniform tubuli, near the lower right 

 hand corner, 28 



2a. Transverse section, showing the small axial, and a portion of the large 

 peripheral region. Where the section exhibits the inner layers 

 of the zooecial walls, a large number of minute foramina are 

 shown. 



2b. A longitudinal section, showing the granular spiniform tubuli, and 



minute connecting foramina. 

 Fig. 3. Rhombopora elegantula, n. sp. A fragment of this species, nat. 



size, 33 



3a. A tangential section, showing small spiniform tubuli, and remarkably 



thick cell-walls. 



3b. A vertical section. Two of the tubes show the true outline of the 

 zocecia. 



Fig. 4. Rhombopora wortheni, n. sp. A fragment of this species, nat. size, 32 

 4a. A longitudinal section, showing the peculiar form of the zooecial 

 walls. 



46. A portion of the surface of fig. 4 enlarged. Shows the typical form 

 of the zocecia, vestibules, and spines. 

 Fig. 5. Rhombopora armata, n. sp. A fragment, natural size, ... 31 



5a. Surface of fig. 5, enlarged. 

 Fig. 6. Rhombopora pulchella, n. sp. A fragment of a branch, nat. size. 31 



6a. Surface of fig. 6, much enlarged. 

 Fig. 7. Rhombopora persimilis, n. sp. A branching fragment of the nat. 



size, 30 



7a. A tangential section. 



7b. Represents a transverse section. 



7c. A longitudinal section, showing spiniform tubuli, and true outline of 

 zocecia. 



7d. The surface of fig. 7, enlarged. The rhomboidal form of the vesti- 

 bules is often more distinct than is shown in this figure. 

 Fig. 8. Rhabdomeson gracile, Phill. A transverse section of this species; 



for comparison with fig. 7b, ........ 25 



8a. A vertical f ection of this species, showing the central tube, the out- 

 line of the zooecial walls, and a few diaphragms. To be com- 

 pared with vertical sections of Rhombopora. 



