﻿HERMATOSTROMA SCHLUTERI. 



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regular, and more pointed than they are in 8. curiosa (see Plate III, fig. 6), but 

 the general skeletal tissue, as shown in thin sections, is decidedly more close 

 and dense. 



Distribution. — This species is of common occurrence in the Middle Devonian 

 Limestones of Biichel (in the Paffrath district), and occurs also in the Eifel. As 

 regards Britain, I possess two examples of an incrusting Stromatoporoid, 

 collected by the late Mr. Champernowne in the Middle Devonian Limestones of 

 Pit Park Quarry, Dartington, which show all the general characters of the 

 present species. Unfortunately the internal structure of these specimens is 

 imperfectly preserved, and though I have no reason to doubt the correctness of 

 my determination, I have preferred to take the descriptiou of the species from 

 specimens collected in Germany, and the specimens figured are also German. 



Genus 4. — Hermatostroma, Nicholson, 188G. 



(General Introduction, p. 105.) 



1. Hermatostroma Schluteri, Nicholson. PL III, figs. 1 and 2; PI. XXVIII, figs. 



12 and 13 ; and woodcuts, figs. 1,16, 

 29,30, 31, and 32. 



Hermatostroma Schluteri, Nicholson. Mon. Brit. Strom., General Introduc- 

 tion, p. 105, 1886 (figured but not 

 described). 



The ccenosteum in this species is massive, and readily splits into thick 

 concentric strata of the nature of " latilarnim'e." The true surface is not known, 

 but the supposed upper surfaces of the laminge are covered with broad and 

 comparatively low, rounded elevations of variable size, which are formed by 

 gentle bendings of the concentric layers (Plate XXVIII, fig. 12). These 

 elevations are about 3 — 4 mm. in diameter, two of them usually occupying a 

 space of about 1 cm., and they do not constitute proper "mamelons," since they 

 do not carry the apertures of the astrorhizse at their summits. Astrorhizas, in 

 fact, appear to be wanting. 



As regards its minute structure, the skeleton-fibre is very thick, and is 

 furnished with an axial canal, which may give off secondary prolongations, but it 

 is not minutely porous. Vertical sections (Plate III, fig. 2) show exceedingly 

 strong " continuous " radial pillars, which traverse many successive interlaminar 

 spaces without a break, and are connected at definite intervals by short and 

 stout connecting processes, which give rise to very regular " concentric laminae." 

 As the connecting processes are rectangular to the pillars, vertical sections show 



