440 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



PAGE 



Billings, E., bibliographic references iii, i6i, 218, 372 



Billingsella, classification of 142, 148 



compared with Eoorthis 104 



Syntrophia canibria 107 



Wimanella 98, 99 



evolution of pi n (pp. 140-141) 



mentioned loi, 103, 109 



pseudospondylium in I59 



appalachia, compared with Wimanella shcWycnsis 100 



hivia, mentioned 300 



coloradoensis, associated fossils listed no 



compared with Billingsella major loi 



Billingsella plicatella 99 



Wimanella simplex loi 



mentioned no 



stratigraphic position and association 192, 193, 196, igS 



thin section of 164, pi. 12, fig. i 



exporecta, pseudospondylium in 159 



highland ensis, compared with Wimanella si)uplex loi 



mentioned 99, 345 



stratigraphic position and association 184, 187 



major, new species loi, pi. 10, figs, i and la 



compared with Billingsella coloradoensis loi 



marion, new species 102, pi. 10, fig. 5 



associated fossils listed 102 



compared with Billingsella salemensis 102 



stratigraphic position and association 212 



plicatella, compared with Billingsella coloradoensis 09 



compared with Wimanella harlajtcnsis 99 



pseudospondylium in 159 



thin section figured 151 



salemensis, compared with Billingsella marion 102 



sp. undt., stratigraphic position and association 183, 195, 209 



Billingsellidae, chemical composition of shell compared with that of 



Orthidse 152 



classification of 142 



compared with Ordovician Protremata 151-153 



defined 147 



derivation from Atremata 152 



diagram showing line of descent 140 



distribution in Cambrian strata 140 



microscopic shell structure in 151-153 



mentioned 99 



number of genera, species, etc., referred to the family, with note on 



distribution 141 



Billingscllinae, classification of 142 



defined 148 



billingsi, see HyoUthes. 



