BRACHIOPODA. 



315 



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

 torily known representatives of the family Thecidew^ in palaeozoic faunas. 



Kayser described, unier 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 RICHTHOFENI A, Kayser. 1881. 



1863. Anomia, db Kosinck. Quarterly Journal Gteol. Soc. London, vol. xix, p. 6, pi. iv, figs. 7-9. 



1863. Anojnia, db Koninck. Foss. Paleoz. de llnde, p. 18, pi. iii, figs. 7-9. 



1881. Richthofenia, Katsbb. Zeilschr. derdeutsch. geolog. Gesellsch., vol. xxxiii, p. 351. 



1882. Antnnia (Richthofenia), Waaqkn. Neues Jahrb. fur Mineral., vol. i, p. 115. 



1883. Richthofenia, Waagbn. Records Gfeol. Survey of India, vol. xvi, pt. i, p. 12, pis. i, ii. 

 1883. Richthofenia, Katsbb. Richthofen'a China, vol. iv, p. 195, pi. xxiv, figs. 6-8. 



1885. Ricfithnfgnia, WAAOEif. Productus-limestone Fossils; Brachiopoda, pp. 733-743, pi. Ixxxii, 

 fi|^. 1 ; pi. Ixxxii A, figs. 1-4 ; pi. Ixxxiii, fig^. 1-19. 



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

 operculated corals, and present some suggestive similarities to the lamellibranchs 



FIO. M8. Fio. M9. Fig. 260. Pro. 251. 



Richthofenia Lawrenciana, de Koninck. 



Fig. 248 The exterior of llie two valves in articalation. 



Fig. 219. LongiluiliDUl section of the pedicle- valve; showing the interior cavity and the cellular shell suhstance. 



Fig, 2S0, The Interior of the pedicle-valve; showing the hinge-line and muscular scars. 



Fig. ai. The interior of the brachial valve. (Waagbn.) 



