CLASSIFICATION OF THE BRACHIOPODA. 105 



Seventeen years later M. d^Orbigny proposed the term Orthisina for exactly the same 

 shells ;^ nor does he allude to the Russian author, whose name Pronites or Hemipronites, 

 might have saved the necessity of a fresh appellation,^ M. d'Orbigny states that he is 

 only acquainted with three species belonging to his section, viz., 0. anomala, 0. Verneuili, and 

 0. adscendens, and seems impressed with a false idea as to the value of the temporary foramen,"' 

 which in middle-aged shells is rarely visible. I feel disposed to extend the limits of 

 OrtMsina, by admitting therein a number of so-called Orthis, with closed fissures, such as 

 0. plana, 0. pelargonata, crenistria, and other similar forms, which would not, I think, be 

 properly placed in Orthis or Strophomena. The section Orthisina seems to connect the 

 two last-named genera, and would be found convenient in arranging and separating a 

 number of species which could not be united without destroying the clearly-defined 

 characters of both Orthis and Strophomena. 



Geol. range. — Orthisina first appeared in the lower Silurian period, and continued to 

 be represented in the Devonian, Carboniferous, and Permian epochs, above which no 

 authenticated species has been hitherto recorded. 



Examples : 0. adscendens, Pander, sp. = excelsa, id. 0. Verneuili, Eichw., sp. ; 0. ano- 

 mala, Schl., sp. ; 0. plana, Pand., sp. ; 0. hemipronites, V. Buch., sp. ; 0. crenistrias, Phil., 

 sp. ? 0. pelargonatus, Schl., sp., &c. 



Genus — Strophomena {Bafinesque) , Blainville, 1825.* 



Type — S. BUGOSA, Ra/.P = S. planumbona or S. alternata. Int., PI. VIII, figs. 157 — 175. 



Anomia (part) of Linnams. 

 Peridiolithus, Hupsch. 



_ _^ — __ — _ — ^ — — — — v~ — . 



1 Considerations Zoologiques et Gcologiques sur les Brackiopodes, Comptes rendus de I'Academie des 

 Sciences, Paris, 1847. — Ann. des Sciences Nat., vol. viii, pi. vii, fig. 30. — Paleont. Frang. Ter. Cretaces, 

 vol. iv, p. 339. — Prodrome, vol. i, p. 16. 



2 I felt embarrassed as to what name to preserve, and therefore consulted several Palaeontologists, 

 among others, Messrs. Salter, Woodward, and Morris, who agreed that as Pander had assembled a number 

 of difi'erent things in his sections, and applied to the same shells several generic names, without pointing 

 out their characters ; and as M. d'Orbigny's name Orthisina had already been adopted by several 

 authors, it was advisable to retain it in preference to those of Pander. 



^ The presence or absence of the foramen is of comparative little generic valve, that character being 

 common to other sections, although in this case difi'ering both from Strophomena, Terebratula, and 

 RhynchoneUa by its position, the aperture being entirely excavated in the substance, and near the extremity 

 of the deltidium, and not in the beak itself, as in many other genera. 



* Nobody has hitherto produced the American author's description or date ; but Blainville describes 

 the genus Strophomena in his 'Manuel de Malacologie,' in 1825, " Coquille 6quilat6rale, reguliere, sith- 

 equivalve ; ayant une valve plate, V autre unpen excavie, articulation droite, transverse, offrant a droite et a 

 gauche d'une suhcchancrure medians, un bourrelet peu considerable crcnele ou dente transversalement, aucun 

 indice de support." 



5 No one seems to have clearly pointed out or identified with certainty S. rngosa of Raf. 



14 



