^6 CANADIAN MICRO-PALEONTOLOGY. 



4. Beyrichia tuberculata (Kloeden). Yar. pustulosa, Hall. 



PI. 11, %. 2. 



Beyrichia pustulosa, Hall. Canad. Nat. Geol., vol. V, 1860, pp. 157, 158, fig. 19; 



Dawson, Acad. Geol., 2nd edit, 1868, and 3rd edit., 1878, 

 ^ pp. 608, 609, fig. 216. 



Beyrichia tuberculata, Jones. Quart. Journ. Geol. Soc, vol. XXVI, 1870, p. 492 ; 



Geol. Mag., 1881, p. 344, pi. x, figs. 8, 9, and 10. 

 Beyrichia Baueri, Renter. Zeitschr. d. D. g. Ges., vol. XXXVII, 1885, p. 640, pi. 



XXV, figs. 7 A, 7 B. 

 Beyrichia tuberculata, Boll, var. pustulosa, Hall. Jones, Q. J. G. S., vol. XLVI, 



1890, p. 18, pi. ii, figs. 1 a, b, c, and p. 552. 



Length 5*0 (hinge-line 4 "5), height 3*0, thickness of carapace 2 mm. 



Fig. 1, Quart. Journ. Geol. Soc, 1890, is one of the Nova Scotian 

 forms of this Beyrichia, and, being an internal cast, is comparable with 

 fig. 8, pi. X, 'Geol. Mag.,' 1881, but it has lost its anterior fourth by 

 fracture ; and the hypertrophy of its antero-ventral lobe makes adifiPer- 

 ence. Although the hinder lobe in fig. 8, ' Geol. Mag.,' is partly broken 

 off, the two specimens may have agreed in this region. As for the 

 valve itself, fig. 9, ' Geol. Mag.,' is quite equivalent (though shorter) to 

 the cast shown in fig. 8, and to the specimen fig. 1, 1890, except that 

 the latter has the hypertrophied lobe, which, however, is not at all an 

 essential or specific feature. * The tubercles (pustules) on the gigot 

 lobe are traceable on each specimen. 



This fig. i, if restored with its valve complete, may be regarded as 

 equivalent to Boll's B. tuberculata, having the enlarged lobe, fig. 1 a, 

 Archiv Meklenburg, 1862, p. 119, without any tubercles on the gigot. 

 This form, and the same without the big lobe, are described and 

 figured by Eeuter, Zeitschr. D. g. Ges., 1885, p. 634, pi, xxv, fig. 2 a and 

 2 B, as B. tuber culata-gihbosa. Fig. 10, ' Geol. Mag'., is not quite perfect 

 along the antero-dorsal margin, but may be regarded as a large growth 

 oi B. tuberculata, with tubercles on the gigot lobe, and with the lower 

 portion of the large anterior lobe preserved, Eeuter's B. Baueri has a 

 close affinity. 



The specimen fig. 1, 1890, labelled " Beyrichia pustulosa, Arisaig, 

 Nova Scotia," is a sandstone cast of the inside of a right valve, coated 

 with haematite. It lies on a small piece of fine-grained micaceous 

 sandstone, almost wholly stained red, but whitish here and there. 



Fig. 2, pi. X, is a cast in the same limestone as that containing B. 

 tuberculata, fig. 3; and, excepting as to its hyjDertrophied antero-ventral 



* Ann. Mag.N. H., April, 1866, pp. 339-342. 



