112 
PALEONTOLOGY OF NEW YORK. 
purpose to distinguish the earlier forms possessing such characters by a sep¬ 
arate name. 
The term Hoivkeospira is suggested, and the division will at present include 
Retzia evax. Hall, Retzia apriniformis, Hall, and Retzia sobrina, Beecher and Clarke; 
all of the Niagara fauna. 
Genus PTYCHOSPIRA, gen. nov. 
PLATE L. 
1834. Terebratula, von Buck. Ueber Terebrateln, p. 76, pi. ii, fig;. 37. 
1841. Terehi’otula, Phillip.s. Pal. Foss. Cornwall, Devon and West Somerset, p. 89, pi. xxxv, fig'. 163. 
1841. Terebratula, d’Arohiac and de Verneuil. Trans. Geol. Soc. London, second ser., vol. vi, p. 368, 
pi. xxxv, fig. 3. 
1849. iSpirigerina, d’Orbigny. Prodrome de Paleontologie, vol. i, p. 100. 
1853. Tei-eln'atula, Schnur, Palisontogi'aphica, vol. ill, p. 184, pi. xxv, fig. 4. 
1855. Retzia, The Sandbergers. Verstein. der rhein. Scbicht. Syst. in Nassau, p. 330, pi. xxxii, fig. 13. 
1862. Retzia, White and Whitfield. Proc. Boston Soc. Nat. Hist., vol. viii, p. 294. 
1863. Retzia, Hall. Sixteenth Ann, Kept. N. Y. Slate Cab. Nat. Hist., pp. 56, 57, figs. 4-6. 
1864. Retzia, Davidson. British Devonian Bi-achiopoda, p. 21, pi. iv, figs. 8-10. 
1871. Retzia, Qdenstbdt. Petrefacktenkunde Deutschl.; Brachiopoden, pp. 433, 434, pi. li, figs. 10-14. 
1871. Retzia, Kavsbr. Zeitschr. der dentsch. geolog. Gesellsch., vol. xxiii, pp. 557, 558, pi. x, fig. 5. 
1882. Retzia, Davidson. British Devonian Brachiopoda, Supplement, p. 29, pi. i, figs. 30, 31. 
Among the species currently referred to the genus Retzia are a few which 
possess a very different exterior from the typical forms of all the retzioid 
genera here discussed. Certain of these fall into a natural group on the basis 
of a very coarsely and sparsely plicated surface, and to this group it is pro¬ 
posed to apply the above designation; it will include the Terebratula feriia, 
von Buell, Retzia longirostris, Kayser, both of the Eifel middle Devonian, and 
the R. sexplicata, White and Whitfield, of the Kinderhook group. 
In Terebratula ferita, which is taken as the typical representative of this division, 
the surface of each valve bears seven radial plications, which are sharply angular 
arid greatly elevated at the margins of the shell. The median plication on the 
brachial valve is usually divided by a fine sulcus, there being a corresponding 
ridge in the sinus of the opposite valve. The beak of the pedicle-valve is erect, 
and truncated obliquely by a circular foramen, beneath which lies a flat deltidium, 
the plates of which are, as in allied genera, more or less completely coalesced. 
The epidermal layer of the shell is finely pitted, the punctations apparently not 
