BRACHIOPODA. 



315 



Thecidea and Pterophloios. If this be true, they constitute the only satisfac- 

 torily known representatives of the family TnEcinF.mjE in palreozoic faunas. 



Kayser described, unler the name Leptodus Richthofeni, a species of Lyttonia 

 from among the fossils collected by Richthofen in China; otherwise these 

 genera are unknown outside of India. 



Genus RICHTHOFENIA, Kaysek. 1881. 



1863. Anomia, de Koninck. Quarterly Journal Geol. Soc. London, vol. xix, p. 6, pi. iv, 6ijs. 7-9. 



1863. Anomia, db Koninck. Foss. Paleoz. de I'Inde, p. 18, pi. iii, tig.s. 7-9. 



1881. Rivhiliofenia, Kaysbr. Zeitschr. dei-deutsch. geolog-. Gesellsch., vol. xxxiii, p. 3.51. 



1882. Aiwmia (RicMhofenla), Waaubn. Neues Jahrb. fur Mineral., vol. i, p. 115. 



1883. RicMhofenia, Waagen. Records Geol. Survey of India, vol. xvi, pt. i, [). 12, pis. i, ii. 

 1883. RicMhofenia, K.atser. Richthofen's China, vol. iv, p. 195, pi. xxiv, figs. 6-8. 



IcSS.i. RicMhofenia, Waagen. Productus-limestone Fossils; Brachiopoda, pp. 733-743, pi. ixxxii, 

 fig'. 1 ; pi. ixxxii A, fig;s. 1-4 ; pi. Ixxxiii, figs. 1-19. 



These peculiar fossils, which bear a striking external resemblance to certain 

 operculated corals, and present some suggestive similarities to the lamellibranchs 



i'lo. 24S. Fro. 249. FlG. 250. Fio. 251. 



Richihofeiiia Lawrenciana, de Koninck. 

 Fig. as. Tlic exterior of tlie two valves in .irticulation. 



Fig. 219. Longiludiual section of the pedicle- valve; showing the iuteiior cavity and the cellular shell substance. 

 Fig. 250. The interior of the pedicle valve; showing the hingeliue and muscular scars. 

 Fig. 251. The interior of the brachial valve. (Wa.^gen.) 



