154 
rite A'inerican Gt'ologtf'if. 
March, ISWr. 
Subfamily Lvtt<>niin.+:, Waagen ISS:;. 
liyttonia, Waagen ISS:}. 
L»'i»t()(lus, Kayser 1S82. 
Oldliamina. Waagen 18S:5. 
Family Pkoductid^, (iray 1840. 
Productiiia, Uiebel 18-16; (■honetinjo and Produotina', Waagen 1884. 
riionetes, Fischer de Waldli. 
1S37. 
Lepta'na, McCoy 1844 (not 
Dalman 1828). 
Anoplia, Hall 1892. 
Chonetella, Waagen 1884. 
Chonostrophia, Hall 1892. 
Chonetina, Krotow 1888. 
(Chonetella, Krotow 1884 (not 
Waagen 1884). 
Daviesiella, Waagen 1884. 
Prodiictella. Hall 1867. 
Prodnctus. Sowerby 1812. 
I'y.xis, Chemnitz, 1784. 
Producta, G. B. Sowerby 1825. 
Arbusculites, IVlurray 1831. 
Protonia, Linck 1830 (not Ka- 
fiiies(iiie). 
Marginifera, Waagen 1884. 
Proboscidella, (Ehlert 1887.. 
Etheridgina. (Ehlert 1887. 
Chonopectus, Hall 1892. 
Strophalosia, King 1844. 
Orthothrix, Geinitz 1847. 
Lepta-nulosia, King 1845. 
Aulosteges, Helmersen 1847. 
? ? Anlacorhynchus, i^ittmar- 
1871. 
Isograniina. ^feek and W.. 
1873. 
Family Rkmithofkxid.e. Waagen 1S85. 
Richthofenia, Kayser 1881. 
Family Orthii)>4':. 
Ortliisida' (i)art),d'Orl)igny 1847 
1884. 
Orthis, Dalman 1828. 
Ortlianibonites, Pander 1830. 
^ Plectorthis. Hall 1892. 
"( Hebertella, Hall 1892. 
Schizophoria, King 1850. 
j Orthotichia, Hall 18!I2. 
! Enteletes. Fischer de Wald. 
880. 
Syrit riclasina. Meek 1865. 
• Woodward 1852. 
Orthina' and E^nteletina', AN'aageni 
. Dinorthis. Hall 1892. 
- Phesiomys, Hall 1892, 
( Orthostrophia, Hall 1883. 
j Dalmanella, Hall 1892. 
I Heterorthis, Hall 1892. 
j Bilobites, Linne 1775. 
I Dicd'losia, King 1850. 
Khipidomella, a]hlert 1890. 
Rliil)idomys, (Elilert 1887' 
( not AVagner.) 
Platystrophia, King 1850.. 
*It ifi not intended, by placing the Okthid.k at the end of the order Protremata, to 
suggest an aberrant development or their derivation from the Pkodictii).*;, for it is be- 
lieved that the orthoid stock had its origin in the Hillinomellio.k. All ortlioids are with- 
out the spondyllum of the Tkuli.acka, and cannot, therefore, be placed in that suborder, 
while the absence of a deltidiuin at maturity places the ORrHin.K after those families 
liaviug this plate in all stages of growth. For other observations see note to Billinos- 
