KONGL. SV. VET. AKADEMIENS HANDLINGAK. BAND 32. N:0 I. 111 



a broken ed^e the sclerenchyma plainly consists of a solid, not spongy mäss, and the 

 microscopic structure in all probability coincides with that of ProtaraBa, as do also other 

 specimens from Wesenberg. The columellar portion or the central area is more prominent 

 in Seebach's specimen as it bas been so much weathered all around. In consequence 

 of what I now have stated, I think that Stylaraja Roemeri cannot be retained as an in- 

 dependant genus nor as a species and that it is rather to be regarded as a form of the 

 highly variable Protarasa vetusta. 



NiCHOLSON described^ a new genus of Silurian Corals under the name of Cleistopora 

 (^ more correctly Clistopora) and asserts that its affinities are with Protaraea. This cannot, 

 however, be the case as it is composed of a porose, reticulated sclerenchyma without any 

 distinct septa in the calicles. 



ProtarcBa vetusta. J. Hall. 

 Pl. xir, figs. 19—24. 



1847. Porites? vetustus J. Hall. Pal. N. York I, p. 71, pl. 25, ligs. 5a, bh. 



1850. Asti-feopora vetusta d'Orb. Prodr. I, p. 25. 



1851. Protarpea vetusta E. & H. Pol. Terr. Pal., p. 208, pl. 14, figs. 6, 6a. 



1851. » » IID. Monographie des Poritides, Ann. Se. Nat. Zool., 3™"= Sér., vol. 16, p. 47. 



? 1856. Diplastraea diffluens ElCHWALD. Bull. de Moscou, p. 111. 

 1860. s » Id. Lethsea rossica I, I, p. 445, pl. 30, tig. llrt, b, c. 



1860. Protaraea vetusla E. & H. H. N. Cor. III, p. 185. 



1866. » » VON Seebach. Zeitschr. d. deutsch. Geol. Gesellschaft, p. 305, Taf. IV, f. 1. 



1866. Stylarasa Eoemeri V. Seebach. Ibid., p. 306, Taf. IV, f. 2. 



1873. Protaraea vetusta LINDSTRÖM. Sv. Und. Sil. Corall., p. 21. 

 1875. » » NiCHOLSON. Geol. Survey Obio, Palreontology 2, p. 221. 



1878—81. » » QUENSTEDT. Petref. Deutschl., p. 54, pl. 145, f. 12, 13, p. 907, pl. 178, f. 37. 



1878. » » NiCHOLS. & Eth. Girvan, pl. 4, fig. 3, 3a. 



1880. Stylarsea Eoemeri LiNDSTR. Fragm. Silurica, p. 31. 



1881. » » Qdenst. Petref. Deutschl., p. 908, pl. 178, fig. 40. 



1882. Protaraea vetusta J. Hall. Indiana 11*'' Rept., p. 378, pl. 49, fig. 4. 



1883. » s Ferd. Roem. Letliaea geogu., p. 456. 

 1883. Stylaraea Roemeri Ferd. Roem. Ib., p. 456. 



1888. » » LiNDSTR. List of Cambr. Sil. Fossils, p. 23. 



1889. Protaraea vetusta Lesley. Diction. Foss. of Pennsylv., vol. 2, p. 774. 

 1889. » 3 Miller. Catalogue, p. 201, f. 209. 



1895. » s WiNCHELL and SCHUCHERT. Geol. of Minnesota, vol. III, pt. I, Palaeontology, p. 94. 



1896. » » Sardeson. Tabulaten, p. 300. 



1897. » » var. magna. WhITEAVES. Palaeoz. Foss. Canada, vol. III, pt. III, p. 155, pl. 18, 



figs. 2, 3, 3a. 



This coral seems to have always grown on other fossils as a thin crust, seldom 

 exceeding 2 millims in thickness. The fig. 21, pl. xii, represents the first foundations 

 of a colony, which is highly deviating in its appearance from the mature form. 



^ Geological Mag. 1888, p. 150. 



