BRACHIOPODA. 2-57 



Phillips,* which t'oriii Mr. Daviuson has reganludf as hut a variety of Phillips' 

 Spirifer crenistria. 



This well known and widely distributed species (according to current au- 

 thority), Spirifer crenistria, Phillips {= Streptorhynchus crenistria), may hence be 

 taken as the type of Orthothetes ; and since tliis fossil, as recognized, is sul)- 

 ject to considerable variation in the regularity and eleviition of the uinl)o of the 

 pedicle-valve, which is usually normal and symmetrical, but sometimes much 

 distorted, it opens the genus to the reception of species in wbicli this irregular- 

 ity is usually present, and to those in which this condition does not appear. 



Genus H I P P A Pt I N Y X, Vanuxem. 1842. 



I'LATli IX, FIGS. K-3li; ANL> PLATK XVa, FICiS. il-U. 



183S. LepicBna unguiformus, Conrad. First Ann. Rept. PaUcont. Dcpt. N. Y. State GftoL Snrvey, 



ji. 112 (not descrilied). 

 1840. StropJtomena U7iguifo)-inis, Conrad. Thinl Ann. Rept. Palieont. Pi'pt. N. Y. State (xeoL Sin'vey, 



p. 203 (not described). 

 18-11. Atrypa u/igitifoniiia, Conrad. Fifth Ann. Rept. Palseont. Dcpt. N. Y. State Geol. Survey, 



p. 36 (not desciibed). 



1842. Hipparkmijx proxhiMS, Vanuxem. Geolog:y of N. Y. ; Rept. Third Dist., p. 124, tig-. 2i), No. 4 



(not H. cimsimUis nor H. similarls, Vanuxbm, p. 124). 



1843. Atrypa imgiiifonnis, (Conrad) Hall. Geology of N.Y.; Rei)t. Fourtli Dist., p. 149, tig. 60, No. 4. 



1859. Oithis ?iipparioayx, Hall. Pal;i;ontoiogy of N. Y., vol. iii, p. 407, pi. lxx.\ix, tigs. 1-4; ]il. xc, 



tigs. 1-7 ; pi. xci, tigs. 4, 5 ; pi. xciv, tig. 4. 



1860. Oi-thls unguiformis, Em.mons. Manual of Geology, p. 129, tig. 11!5. 



1881. Orthis unguiformis, Davidson. '? Bi'achiopoda Budleigh-Salterton Pebble-bed, j). 347, pi. xxix, fig. 1. 



1883. ^trepUrrhynclms lilppanonyx. Hall. Second Ann. Rept. N.Y. State Geologist, pi. 39, figs. 33-36. 



Not Orthis liippariony.):, Schnuk. 1853. Palsontographica, vol. iii, p. 217, pi. xl, tig. 1. 



Not Orthis hipparhinyxK Davidson. 1865. British Devonian Brachiopoda, p. 90, pi. xvii, figs. 8-11. 



The remarkable shell described by Dr. Vanuxem as Hipparionyx proximus, so 

 far as known, is the only representative of a peculiar association of streptor- 

 hynchoid characters. The name Hipparionyx has not been in general use, 

 though, in the broad application of the generic term, which has been customary 

 in this group of shells, it should have had precedence over Streptorhynchus. 

 Schnur, in 1853, regarding what he believed to be a similar shell from the 

 Eifel as an Orthis, took the liberty of changing Vanuxem's name for the species 



* Geology of Yoi-kshire, vol. ii, p. 220, pi. xi, fig. 4. 1836. 



t British Carboniferous Brachiopoda, p. 127; British Devonian Brachiopoda, p. 81. 



