Class t;fi cation of tin' Bi'achlopodo. — Scl,iic],oi-t. 155 
Order Telotremata,* Beecher 1S!»1. 
Kampylopegmata (part), WaaKen 1883; Pegmatobranchiata (part), 
Neuniayr 1883. 
Suborder RostPaeea,t 11. suborder. 
Family Hhynciion 
Hypothyridiu (part), King 1850 
Hhynchotrema, Hall 1860. 
Rlij'nchotreta, Hall 1870. 
Uncinulus, Bayle 1878. 
Hypothyris, King 184() (not 
Phillips 1841). 
Stenocliisma (Conrad 1SP)9). 
Hall 1867. 
Leiorhynchus, Hall 1800. 
Rhynchoporina, ffihlert 1887. 
Rhynchopora, King 1856 ( not 
Illiger and Latreille). 
Terebratuloidea, Waagen 188:-). 
Acanthothyris, d'Orbigny 1 850. 
Norella, Bittuer 18J)0. 
Hemithyris, d'Orbigny 1847. 
Peregrinella, (Ehlert 1 887. 
ELLii).«, (xray 1848. 
; Rhynchonellina\ Waagen 1883. 
Rhynchonellina, Gremmellaro' 
1871. 
Dimerella, Zittel 1870. 
Cryptopora, Jeffrey's 1861>. 
Atretia, Jeffreys 1876. 
Neatretia, (Ehlert 1891. 
Rhynchonella, Fischer de Wald. 
1809. 
Oxyrhynehus, Lihwyd 1699 
(not Aristotle). 
Hhyngonella,Kronn 1849. 
Bicornes, Quenstedt 1851. 
Uncinulina, Bayle 1878. 
Halorella, Bittner 1890. 
Austriella, Bittuer 1890. 
Eatonia, Hall 1857. 
? Branconia, Cagel 1890. 
?Family Ki('HWAi,i)iii>.K,t n. t'aui. 
Eichwaldia. Billings 1858. 
Dietionella, Hall 1867. 
*The Tklotrkmata diirinj; nepionic and early nealoijic growth have an open triangular 
Assure or delthyrinni in the apex of the ventral valve through which the pedicle emerged. 
In later nealogic and ephebolic growth, tlie fissure is more or less closed anteriorly 
through the development from the mantle of two plates, one from each wall of the del- 
thyrinni, which usually coalesce centrally. These plates are known as the "deltidial 
plates." In such forms as Cyrtia, dyrlind, and Si/rhigothyris, where the ventral cardinal 
area is very high, tlie deltidial plates are anchylosed, the mantle in this region becoming 
continuous and the plate growing as one piece. The Telotremata, therefore, develop a 
covering to the delthyrium in an entirely different manner from the other orders during 
nealogic and e|)hebolic growth. 
iHogtrum, a beak. Tlie genera of this suborder are rostrate sliells without a spon- 
dylium or any calcareous brachial 8upi)orts other than short or long, straight or slightly 
curved, freely terminating crura. In the IIelicopeomata, the latter consists of two cal- 
careous spiral lamella', wliile in the Anctlobkachia there is a loop. 
XThe genus Eichwali/ia in very peculiar in not liaving a distinct articulation of the 
valves as in otiier Authuopomata and further in the SIphonotreta-like i)edicle ojieii- 
ing. Those ( liMracters are considered by some writers to indicate attinities with the Lv- 
opomata, and it is to tliis subclass the genus has lieeii doubtfully referred by authors. 
In Eichwa/i/id tliere is, liowever, a method by wliich articulation takes place consisting 
of narrow grooves along the lateral edges onthe dorsal valve and corresponding ridges 
or teeth in the ventral. 
The writer thinks that Kichwalilia had its origin either in tlie Riiyncii<>nei.i.ii>.« or 
Pentamkiud.'e, and not directly through any inartlcul.ite pliylum; that the peculiar ped- 
icle opening is a modification of the open or closcil tiiungiilar delthyrium of rostrate 
species, just as the nepionic circular foramen iw Siiilimiotreta becomes changed to an 
elongate fissure by progressing anteriorly through the shi'll. 
