STACHYODES VERTICILLATA. 221 



though it is possible to determine their generic affinities, they do not throw any 

 additional light upon the structure of the genus Hermatostroma. 



Hermatostroma episcopate differs from H. Schluteri, the only other recorded 

 species of the genus, in the following characters : 



(a) The astrorhizal system of H. episcopate is very well developed, and astro- 

 rhizal cylinders are present; on the other hand, in H. Schluteri astrorhizae are 

 apparently not developed in any recognisable form. 



(b) The skeletal tissue of H. episcopate is not so coarse as that of H. Schluteri, 

 and the axial canals of the radial pillars are proportionately less developed. 



(c) The skeleton-fibre of H. episcopate, apart from the presence of the axial 

 canals above spoken of, is minutely porous ; whereas in H. Schluteri the skeleton- 

 fibre, but for the above-mentioned canals, appears to be solid. It is to be 

 remembered, however, that the porous character of the skeleton-fibre can be 

 recognised in H. episcopate in certain specimens only, and it is therefore quite 

 possible that the apparently solid nature of the skeleton-fibre in the only known 

 example of H. Schluteri may be simply the result of imperfect preservation. 



(d) The interlaminar spaces of H. episcopate are usually intersected by more 

 or less numerous " interlaminar septa," which generally have a direction more or 

 less conforming to that of the concentric lamina? themselves. Similar structures 

 do not occur in any marked form in H. Schluteri. 



Distribution. — Hermatostroma episcopate is not uncommon in the Devonian of 

 Shaldon and Bishopsteignton, and occurs more rarely in the pebbles of the 

 Triassic conglomerates at Teignmouth. 



Family— IDIOSTROMID^E. 



Genus 1. — Stachyodes, Bargatzhij, 1881. 

 (Introduction, p. 107.) 



1. Stachyodes verticillata, M'Coy sp. PI. VIII. figs. 9 — 14; PL XI, fig. 5; 



and PI. XXIX, figs. 1 and 2. 



Steomatofora (Oatjnopoea) yerticillata, M'Coy. Brit. Pal. Foss., p. 66, 



woodcuts a and b, 1851. 

 Stachyodes eamosa, Bargatzky. Zeitschr. der deutschen Geol. Ges., Jahrg., 1881, 



p. 688. 

 verticillata, Nicholson. Mon. Brit. Strom., General Introduction, 

 p. 107, pi. viii, figs. 9 — 14 ; and pi. xi, 

 fig. 5, 1886. 



