198 



BRITISH STROMATOPOROIDS. 



or more calcareous partitions, and may possibly be connected with reproduction, 

 and may correspond with the ampulla? of the recent Stylasterids. 



Fig. 27. 



A a 



t 

 Fig. 27. — A. Vertical section of Parallelopora capitata, Goldf. sp., from the Devonian Rocks of Hebborn 

 (Paffrath district), enlarged 12 times. B. Tangential section, similarly enlarged, a a. Supposed 

 " ampullae." c c. Large tabulate tubes belonging to the astrorhizae. t t. The ordinary zooidal tubes. 



The skeleton-fibre is stout, and possesses a tubulated or perforate structure 

 (Plate XXV, fig. 13), similar to that previously described in P. Goldf ussii, Barg., 

 though, owing to the imperfect state of preservation of the majority of specimens, 

 this can only be clearly made out in an occasional example. The ccenosteal 

 tissue, as seen in tangential sections (Plate XXV, figs. 10 and 11 ; and woodcut, 

 Fig. 27, b), is irregularly reticulated, and is traversed by the irregularly distributed, 

 tabulate astrorhizal canals, and by the apertures representing the transversely 

 divided zooidal tubes. As seen in vertical sections (Plate XXV, fig. 12 ; and 

 woodcut, Fig. 27, a) the skeleton is composed of stout, approximately parallel 

 radial pillars, which are connected at short intervals by thinner or thicker cross- 

 bars, tolerably regular and close-set " concentric lamina? " being in this way some- 

 times developed. The radial pillars are separated by well-developed zooidal 

 tubes, which are intersected by numerous straight or curved " tabular. " About 

 four zooidal tubes, with their intervening radial pillars, occupy the space of 2 mm. 

 measured transversely. Vertical sections also show the large rounded apertures 

 of the transversely divided astrorhizal tubes as well as the supposed " ampulla? " 

 above spoken of, these structures communicating to such sections (Plate XXV, 

 fig. 12 ; and woodcut, Fig. 27, a) a very characteristic aspect. 



Obs. — I do not feel at all certain as to the identification of this species with the 

 Tragos capitatum of Goldfuss ; since no thin sections of the original of the latter 

 are in existence, and the preparation of such might very possibly show that the 

 form which Goldfuss had in view was really the subsequently described P. Gold- 

 fussii of Bargatzky. Owing to the very close general resemblance between the form 



