PLATE 19. 



Fig. 1. 429. 1. Rhinopoka verrucosa. ( Pag. 48.) 



1 a. Fragment of the natural size. 



1 6. A fragment of the natural size, showing a ramose elevated ridge ruinn"ng over the s\irface. 



1 f . A portion enlarged, showing the form and arr.mgcment of the cells. 



Fig. 2. 430. 2. Rhinopoba titbulosa. ( Pag. 49.) 



2 o. A fragment of this spe'cies, of the natural size. 



2 6. A section of 2 a, showing the form, the interior being filled withshaly riatter. 



2 c. A portion of the surface enlarged, showing the form and arrangement of the cellules. 



Fig. 3. 43l. 4. Retepora angulata. (Pag. 49.) 



3 a. The poriferous face of a portion of a fl-ond (the specimen preserved in shale). 



3 4. The non. poriferous face of another individual. 1 c. A portion of 3 a enlarged. 

 _ 8 d. A portion of the non-i)oriferous face of 3 6 enlarged. 



8 «, /, g, h. The poriferous face of two small ft-agments from calcareous strata, natnral size and enlarged. 

 In these the pores are very conspicuous, and the fencstrulos differing in size and form in the two spe- 

 cimens. 



Fig. 4. 432. 1. Fenestella prisca? ( Pag. 50.) , 



4 a. The base of a frond, showing the external poriferous face. 4 6. A portion of the same enlarged. 

 4 c. The non-poriferous face of a portion of a frond. 



4 d. Several of the fenestrules near the base enlarged, showing di.stinctly tlie oval form. 



4 e. Several of the fenestrules enlarged (from a portion of the surface which has been worn down), showing 



a quadrangular form. 

 4 /. A surface of stone, preserving the impression of the poriferous and non-porifbrons faces of this coral. 

 4 g. A portion enlarged, showing the thin sharp lines of impression of the branches of the poriferous face. 

 4 h. Enlargement of the spaces filling the fenestrules on the non-poriferous face. 



4 i, k, I, m. Similar enlarged portions of the impressions of the two faces of the coral. 



Fig. 5. 433. 2. Fenestella tentji.'. ( Pag. 51.) 



6 a. A portion of the frond of this species, natnral size. 



5 6. A portion of the poriferous face magnified. 



5 c. A portion of the non-poriferous face magnified, showing distinctly the form of the fenestrules. 



