EXPLANATION OF THE PLATES AND WOOD-CUTS. 



the position of the internal lamellae, and by concentric rugas and fine lines (Fig. 7.). 

 Internally formed of numerous lamellae, which are spirally contorted in the centre, 

 and bifurcate as they radiate more or less regularly to the circumference (Fig. 7 a.). 

 No central cavity crossed by chamber-like septae, that part of the coral being occu- 

 pied through its whole height by the spiral lamellae (Fig. 7 a.). 



Loc. Plymouth and Newton Bushel, abundant. 

 Figs. 8 to 8 c?. Cyathophyllum ceespitosu7n (Goldfuss, Tab. 19, f. 2.). 



An abundant coral in the Devonian limestones, but seldom well preserved, the 

 exterior portions having been in general removed by atmospheric action. Fig. 

 8 a. represents a common weathered specimen ; 8 c. a section of a similar branch ; 

 8 6. a section of one in which the exterior has been less effectually removed. Fig. 

 8 represents a specimen of hard limestone, in which the matrix has preserved the 

 exterior portions of the coral. Fig. 8 c/. is a vertical section, exhibiting transverse 

 chamber-hke plates, and part of another branch or individual, which had sprung 

 from a gemmule deposited on the side of the main coral, and not originated in the 

 subdivision of the older animal. The sections. Figures 8 i. 8 c. and 8 d. in the ab- 

 sence of the central style, sufficiently distinguish this coral from one of similar ex- 

 ternal form, abundant in the mountain-limestone. 



Loc. Newton Bushel, Plymouth, Torquay, &c. 

 Fig. 9. Scyphia turbinata (Goldfuss, Petref. PI. II. f. 13.). 



Two pyritous specimens imbedded in slate, from the vicinity of Plymouth, are in 

 the cabinet of the Rev. R. Hennah. 

 Fig. 10. Fenestella antiqual (Silur. Syst. PI. XV. f. 15, 18.). 



Gorgonia anttqua (Goldfuss, Petref. PI. XXXVI. f. 19.), 



This is also an abundant coral in the slate rocks of the Devonian system ; but the 

 essential characters are seldom preserved. It presents generally a more or less deli- 

 cate net-work (Fig. 10) or cast of the interior surface of the coral ; and occasionally 

 impressions of the bifurcated lamellae of the exterior surface (10 a.). Casts of the 

 pores have been also observed in a few instances, and their arrangement led to the 

 belief, when first noticed, that the coral belonged to a new, well-distinguished 

 species of Fenestella. Instead of being arranged in two rows, separated by a 

 ridge or projecting angle, as in Fenestella anttqua (Silur. Syst. PI. XV. Fig. 16. 

 Goldf. PI. XXXVI. f. 9.), the pores or their casts are in contact and disposed 

 alternately, so that the projecting curve of one pore occupies the space between 

 two pores in the adjacent row (Fig. 10 b.). On examining however some crushed 

 specimens of Fenestella from Meinershagen, the characters of the Devonian co- 

 ral and of Fenestella antiqua were noticed in portions of each specimen ; and 

 though the detached fragments could not be proved to have been once united, 

 yet Uttle doubt can exist of their being portions of the same coral, and that the 

 alterations in character must be ascribed to changes in the animal at different pe- 

 riods of growth. Fig. 10 b. is a portion of Fig. 10 a. mag. 



Loc. Petherwin, Fowey, Plymouth, in soft yellow slate, Newton Bushel, 

 Saunton, Linton, &c. 

 Fig. \\ to W b. Cystiphyllum Damnoniense (Sp. n.). 



