BRACHIOPODA. 



313 



Genus LYTTONIA, Waagen. 1883. 



1878. Bactrytiium, Waaqbn. Re(;or(]s Geol. Surv. India, vol. xi, pp. 186, 187. 



1880. Thecldea, Zdgmatbr. Untei-s. ilber rhat. Brachiopoden ; Beitr. zur Palaon. von Oesterreich- 

 Ungarn, I, p. 22. 



1882. Leptodiui, Katsbh. Richthofen's China, vol. iv, p. 161. 



1883. Lyttonia, Waagbn. Productus-limestone Fossils ; Biachiopoda, pp. 396-403, pi. ixix, figs. 1-3 ; 



pi. XXX, fig.0. 1-11. 



Shells of great size, highly inequivalve and very irregular ; frequently with 

 broad lateral expansions. 



Pedicle- valve convex, thick ; apex not distinct; hinge-line short and straight ; 

 teeth faintly developed. On the interior are numerous ridges extending in 

 slight curves toward the lateral margins; in the median line is a smooth space 

 bearing a central vertical ridge. 



Fio. 243. Fig. 2«. 



Lyttonia nobilit, Waagen. 

 Fig. 243. Cardinal part of a pedicle-valve; etiowing tlie liinge-Iine, median and lateral septa. 

 Fig. 244. A. portion of the interior of a brachial valve. 



(Waagen. I 



Brachial valve operculiform, not extending to the margins of the opposite 

 valve. Cardinal process small and bilobed ; median surface of the interior 

 with divergent grooves corresponding with the ridges of the other valve. 



External surface covered with flexuous lines of growth. 



Shell-substance punctate in the inner layers. 



Type, Lyttonia nobilis, Waagen. Carboniferous. India and China. 



