146 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 6, 



pteridis, give the flora of this coal-field a certain resemblance to that 

 of central France. The absence of indications of Lepidodendron, 

 Sigillaria, and Calamites (if it be not merely accidental), is a very 

 remarkable pecuUarity. 



Appendix B. — Description of the Neiv Species of Zoophyta and 

 MoLLUscA. By Daniel Sharpe, Esq., F.R.S., G.S. 



DisTEiCHiA*, Sharpe. 



Polyparium fi'onclosum, reticulatum, bi-laminosum : laminae celluliferse, 

 tubulis clausis, transversis conjimctse: cellulse tubulosa; externe de- 

 biscentes. 



Coral consisting of reticulated fronds, formed of two parallel 

 layers of cells, connected by numerous closed transverse tubes : cells 

 tubular, arranged longitudinally side by side, and opening outwards 

 obliquely at their upper extremity. 



These corals difi*er from Eschara and Flustra in the more tubular 

 form of their cells, and in having the layers of cells separated into 

 two parallel walls, which are only connected by numerous trans- 

 verse tubes. They appear to have contained very little calcareous 

 matter. 



DiSTEICHIA RETICULATA, n. S. Pl. VII. fig. 8. 



D. reticulata; ramis planis, interstitiis subsequaUbus, anastomosantibus : 

 ramis junioribus longitudinaliter striatis, celluliferis; adultis, cellulis 

 obtectis, tubis transversis prominentibus. 



Reticulated with branches nearly similar throughout, and equal 

 in breadth to the meshes between them ; branches covered when 

 young with longitudinal strise showing the forms of the tubular cells ; 

 when old the strise are obliterated, the cells cannot be distinguished, 

 and the blunt closed ends of the transverse tubes project beyond the 

 wall of the coral producing a finely mammillated surface. Trans- 

 verse tubes larger than the polyp-cells. 



The general form of the coral has not been seen, nor can the shape 

 of the mouths of the cells be distinguished. 



The species seems to have reached a large size, as one of the 

 fragments exammed is more than 2 inches long ; the branches vary 

 from l^th to |^th of an inch in breadth ; at the lower part the walls 

 are nearly -^^^1^ of an inch apart ; at the upper part they are less than 

 half that distance from each other. The transverse tubes are very 

 numerous. 



Found in the upper division of the Lower Silurian formation at 

 Sazes and the Porto de Santa Anna, in the Serra de Bussaco. 



Plate VII. fig. 8. a. A specimen of the natural size. 



b. Magnified portion of a young branch, with the surface partially 

 broken off, disclosing the broken ends of the transverse tubes. 



* DisteicMa, having two walls. 



