186 BRITISH STROMATOPOROIDS. 



Triassic conglomerates of Teignmouth. In Germany the species is tolerably 

 abundant in the Middle Devonian Limestones of Hebborn and Biichel in the Paffrath 

 district. A single poorly preserved example, which I collected at Gerolstein, 

 differs from the ordinary form of the species in having a laminar coenosteum. 



8. Stromatopora Bucheliensis, Bargatzhj sp. PI. X, figs. 5 — 7, and PI. XXIII, 



figs. 4 — 7. 



Caunopoea BticHELiENSis, Bargatzky. Die Stromatoporen des rheiniscben Devons, 



p. 62, 1881. 

 Steomatopoea bucheliensis, Nicholson. Monogr. Brit. Strom., General Intro- 

 duction, p. 23, pi. s, figs. 5 — 7, 

 1886 (figured but not described). 



The coenosteum in this species is very variable in form, being mostly either 

 massive or lobate, but being sometimes composed of slender cylinders united in 

 bundles, or being in rare cases laminar in shape. A basal epitheca is present in 

 the laminar examples, as, probably, in the massive specimens also. 



Most specimens show a more or less distinct zonal mode of growth, the suc- 

 cessive zones or strata of the coenosteum hardly assuming the character of proper 

 " latilaminas," since they are directly continuous with one another, and thus mark 

 but incomplete intermissions of growth. 



Whatever may be the form of the coenosteum, the concentric laminae are 

 simply curved, and " astrorhizal cylinders" are not developed, the surface being 

 thus free from " mamelons." The surface shows a minute reticulation, the 

 rounded or oval pores of which represent the apertures of the zooidal tubes. 

 Astrorhiza3 are numerous, but are of small size, with few branches, their centres 

 being usually placed at distances of 10 mm. or more apart. 



The skeleton-fibre is minutely porous, and has a diameter of ^ or ^ mm. The 

 ccenosteal tissue is of the reticulate type (Plate XXIII, fig. 7 ; and woodcut, 

 Fig. 20, c), the radial pillars being united into a continuous network by horizontal 

 or oblique bars of the same thickness as themselves. As seen in cross-sections, 

 the ccenosteal mesh is close, with narrow and often sinuous interspaces repre- 

 senting the transversely divided zooidal tubes. Vertical sections (Plate XXIII, 

 fig. 6 ; and woodcut, Fig. 20, d) show that the radial pillars are distinctly recog- 

 nisable, and that the coenosteum is traversed by numerous narrow zooidal tubes 

 which are abundantly furnished with cross-partitions or " tabula?." About seven 

 zooidal tubes, with their intervening pillars, occupy a space of 2 mm. measured 

 transversely. 



Obs. — The coenosteum of 8. Bucheliensis, Barg., is mostly of a lobate or sub- 



