PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 691 
similar to that of Glassia but with cones directed medially and toward the brachial 
valve. 
Genotype-—Camerella panderi Billings, Canadian Nat. Geol., vol. 4, p. 302, 
1859. 
Discussion—This genus has a very obvious camerelloid exterior appearance 
but it differs from the members of the subfamily in being much more rotund and 
in not having an erect beak. IJdiospira differs from Glassia which it resembles 
in the form of the spire, in exterior and interior details. [diospira has a strongly 
uniplicate anterior commissure although the fold of the brachial valve is seldom 
very prominent. The folding usually takes the form of an abrupt wave of the 
commissure and the development of a fairly strong tongue on the pedicle valve. 
Idiospira also has, in some species, more or less well developed costae along the 
margins. 
Internally Idiospira differs from Glassia in possessing strong dental plates, a 
subdued median ridge, and a wide foramen. The spire is different in having the 
loose coils of the cone directed obliquely inward and toward the brachial valve 
rather than inward as illustrated for Glassia. 
IDIOSPIRA ? INORNATA (Weller) 
Camarella inornata WELLER, Geol. Surv. New Jersey, Rep. on Paleont., vol. 3, p. 157, pl. 10, 
figs, 8-10, 1903. 
Although the interior characters of this species were not determined by Weller 
and the types have not been reexamined in this study, the description and figures 
make it clear that this species is not a Camerella. The tendency toward emargina- 
tion of the anterior margin, the wave of the anterior commissure toward the 
brachial valve, the subequal depth of the valves, and the closely appressed beak 
of the pedicle valve are suggestive of assignment to [diospira. 
Horizon and locality —Jacksonburg formation in New Jersey: On the hill 
just east of the station, near Hainesburg, Delaware Water Gap (15’) Quad- 
rangle. 
IDIOSPIRA PANDERI (Billings) 
Plate 108, F, figures 26-32; plate 195, F, figures 33-37; plate 195, H, figures 42-46 
Camerella panderi BiLtincs, Canadian Nat. Geol., vol. 4, p. 302, 1859.—LocAn, Geol. Canada, 
p. 143, fig. 78, 1863—HALL and CrarkeE, Pal. New York, vol. 8, pt. 2, p. 220, pl. 62, 
figs. 19-23, 1893.—? Raymonp, Ann. Carnegie Mus., vol. 7, p. 250, pl. 36, figs. 31, 32, 
I911.—WILson, Geol. Surv. Canada, Bull. 8, p. 118, pl. 11, fig. 2, 1946. 
Two specimens of this species in the National Collection were prepared to 
show the spire. These revealed a fairly tightly coiled spire with the apices di- 
rected medially and obliquely toward the brachial valve. The details of the cardi- 
nalia furnished in the generic description were also taken from specimens of this 
species. Idiospira panderi has been widely identified in Trenton rocks of this 
country and Canada, but a revision of these is in order. The number of speci- 
mens of this genus in the National Collection is small, but a number of new 
species are here separated. 
