PARALLELOPORA CAPITATA. 197 



2. Parallelopoka capitata, Goldfuss sp. PI. XXV, figs. 10 — 13. Woodcuts, 



Figs. 26 and 27. 



Teagos capitatum, Goldfuss. Petrefacta Germanise, p. 13, Taf. v, fig. 6, 1826. 

 Stbomatopoea capitata, D'Orbigny. Prodr. de Paleontoiogie, p. 51, 1850. 



— concenteica, Bargatzky (pars). Die Stromatoporen des rhein- 



ischen Devous, p. 54, 1881. 

 Idiosteoma capitatum ? Nicholson. Monogr. Brit. Strom., General Introduction, 



p. 63, fig. 8, and p. 104, 1886. 



The coenosteum in this species is of the massive type, and is usually spheroidal 

 or pyriform in shape (woodcut, Fig. 26), being attached by a small portion of its 



Fig. 26. 



Fig. 26. — Side view of a small specimen of Parallelopora capitata, Goldf. sp., from the Middle 

 Devonian of Hebborn (Paffrath district), of the natural size. 



under surface, and not having a basal epitheca. The coenosteum did not attain a 

 great size, most examples being from 2 to 6 cm. in diameter. Growth is 

 not distinctly latilaminar, and the concentric laminae are generally simply curved 

 or undulated, the surface being thus approximately smooth or simply nodulated. 

 When well preserved, the surface shows a coarse vermiculate reticulation, 

 corresponding with the form of the skeletal network, along with large and 

 irregularly distributed astrorhizal canals (woodcut, Fig. 26), but parts of the 

 surface may be concealed beneath an apparently imperforate calcareous membrane. 



Astrorhizaa are developed in an irregular manner, their tubes (woodcut, 

 Fig. 27, c c) being of very lai'ge size, and furnished internally with numerous 

 transverse calcareous partitions (" astrorhizal tabulos "), which sometimes assume 

 a subvesicular character (Plate XXV, fig. 10). 



Sometimes connected with the astrorhizal tubes, or at other times inde- 

 pendently scattered throughout the coenosteal tissue, are large, lenticular, oval, 

 or spherical vesicles, which are apparently destitute of proper walls, and are about 

 a millimetre in average diameter. These vesicles are occasionally crossed by one 



