TORNATELLIDiE. 465 



Order— OPISTHOBRANCHIATA, Milne-Edwards. 



SuB-ORDEE— TBOTIBRANCHIATA, Guvier. 



IST.B. — The fossil Opistbobrancliiata have lately received a large share of 

 attention in M. Oossmann's admirable work ' Essais de Paleoconchologie comparee ' 

 (Premiere livraison, Fevrier, 1895) ; and still more recently in his splendid 

 Monograph, ' Etudes siir les Gastropodes des Terrains Jurassiques,' now in course 

 of publication in the Memoirs of the Geological Society of France. This author 

 greatly favours the subdivision of families and genera. Thus we find the 

 following families enumerated from the Jurassic rocks, — Actaeonidae, Tornatinidae, 

 Bullidge, Aceridae (nov. fam.), and Aplustridae. M. Cossmann also includes 

 Ceritella and Fibula amongst the Opistbobrancliiata under Tubiferidee (nov. fam.). 

 The genera and sections are also largely multiplied. Without in the slightest 

 degree questioning the scientific value of these subdivisions, it is proposed to group 

 the Opistbobrancliiata of our Inferior Oolite, for present purposes, under the 

 families Toruatellidae (Actfeonidae) and Bullidfe. 



Family— TOW^ATEJjLIBM (Act^onid.e). 



" Shell external, convoluted, ovoid, conoidal, sijire depressed or prominent ; ivliorls 

 tolerably numerous, without internal absorption, aperture entire, narroiv.^^ — Fischer. 



N.B. — The following genera, subgenera, and sections of this family are 

 recognised by M. Cossmann as occurring in the Inferior Oolite, viz. Tornatellaea, 

 Conrad (e.g. T. pulchella, Deslong.) ; Actxonina, d'Orbigny (e.g. A. gigantea, 

 Deslong.) ; Striadseonina, nov. sect. (e. g. Att. SartJiacensis, d'Orb.). Cylindro- 

 hdlina, von Ammon (e. g. Act. Scarburgensis, Lycett ; Cylindrites, Morris and 

 Lycett (e.g. Act aeon acutus, Sowerby). 



Trochactseonina, Meek, is also quoted from the Bathonian (e. g. Act. ventricosa,. 

 d'Orbigny, and Cassis Esparcyensis, d'Archiac). 



In the present instance it is proposed to retain the older generic classification 

 of the TornatellidjB of the Inferior Oolite, whilst indicating as far as possible the 

 equivalents under the new system. For the most part the specimens are not 

 sufficiently well-preserved to show the finer points. 



