sciir.iiKKT ] CLASSIFICATION OF PKOTREMATA. 135 



Clitaiiiboiiites Pander, 1830. I'olytd'cliia Mall and Clarke, 1892. 



rioiiites I'auder, 1830. Ileillipioilites PaildcT, 1830. 



(Joiiiiiiibonites raiuler, iSoO. j Sceuidiiiin Ililll, 18G0. 



Orthisiua d'Orl.iguy, 1817. I Mystrophora Kayscr, 1871. 



2. Family SYNTKOPJllIDJ^ Scliuclieit, 1800.' 

 Stricklandiniidiu (partiin) Hall and Clarke, 1895. 

 Primitive Pentameracea with long, straight cardinal areas, deltidia, 

 and cniralia. 



Syntrophia Hall and Clarke, 1802-93. 



2a. Family POKAMBONITIDyE Davidson, 1853.- 



Poi-iiiiil)ouitiii:i' (Jill, 1871; Poramboiiitida^ (partiui) Nastliug, 1883; Camaiellidii; 

 (partiin) Hall and Clarke, 1895. 



Pentameracea intermediate in structure between the Syntrophiidie 

 and Pentameridic, in that the deltidium and the straight cardinal 

 areas of the former fainily tend to obsolescence, particularly the del- 

 tidium. The PorambonitidiB approach the latter family in tending to 

 develop a rostrate shell. Cruralium ])resent. 

 Camarella Billings, 1850 (emend ; Brauconia Gagel, 1800. 



Porambonites Pander, 1830. 



Priarabouites Agassi/., 1817. 



Isorhynchiis King, 1850. 

 No'tlingia Hall and Clarke, 1803. 

 ?Lycophoria Lahusen, 1885. 



Hall and Clarke, 1803). 

 Parastrophia Hall and Clarke, 



1803. 

 Auastrophia Hall, 1807. 



P.rachymerus Shaler, 1865 (not De- 

 ,jeau, 1834). 



2b. Family PENTAMEKID.F McCoy, 1844. 



Hypotbyridai (partiin) King, 1850; Pentameridii' Hall, 1867; Camer()i>lioriin;(3 

 Waagen, 1883; Peutamerinni Gill, 1871; W'aagen, 1883; Porauibonitida- (iiartini) 

 Noetlmg, 1883; Stcnochisinatina- and Concbidiinie ffiblert, 1887; Camarellidi<> 

 (partnii), Stncklandiniida- (partim), and Ajupbigenidie Hall and Clarke, 1S95. 



llostrate Pentameracea rarely with straight cardinal areas. Del- 

 tidium commonly absent, but sometimes present as a concave i)late, 

 being the reverse of the ordinary form of the deltidium and due to the 

 incurved beaks. Cruralium present. 



Stricklandinia Billings, 1803. Conchidium Linne, 1753. 



Stricklandia Billings, 1859. , Antiibynchouella Qncnstedt, 1.S71. 



Pentamerus Sowerby, 1813. j Zdimir I'.arrandc, 1879. 



IVntastrio I51ainville, 1824. ' Oypidia Dalman, 1S28. 



Cai)cllinia Hall and Clarke, 1803. Clorinda. Barrande, 1870. 

 Pentamcrclla Hall, 1807. Bairandella Hall and Clarko, IS93. 



Gypidula Hall, 1807. 1 Enantiosphen AVidborne (llolzap- 



Sioberella n:blert, 1SS7. ^^1)' ^^^^' 



Camarophorella Hall and Clarke, : Gamarophoria King, 1840. 



lS\)i\. ' StenocbisuiaDall, 1877; (Kblcrt, 1887 



Amphigenia Hall, 1807. | ^"•'* ''""•■^'•'' ^''^''^- 



' Text Wook of Piileontology, by /ittel and Eastman, 1896, p. ;f20. 



2 Since Hall and Clarke's family Camarellidai (1805), after removing Camaioijhoria and Caniaro- 

 pliorella, is based upon tlie same family characters as those of the Poramltonitidie (1853), as Poram- 

 bonites IS now interpreted, Davidson's family is retained on the {ground of priority. 



