386 Messrs. Jones, Parker, and Kirkby on the 



XLV. — On the Nomenclature of the Foraminifera. By Prof. 

 T. Rupert Jones, F.G.S.,'W. K. Parkee, F.E.S., and 

 J. W. KiRKBY, Esq. 



[Plate XIII.] 



Part XIII. The Permian Trochammina pusilla and its Allies'^. 



§ I. A minute serpuloid fossil occurring abundantly in the 

 Permian Limestone of the British Islands and Germany at- 

 tracted the notice of paleontologists twenty years ago. Its 

 tubular and variously contorted shell suggested an Annelidan 

 relationship, though its minute size seemed to contradict that 

 notion. Prof. W. King had, however, from the first, formed the 

 idea of its being related to the Foraminifera ; but no near ally 

 among the existing Rhizopods was recognized until 1856, 

 when one of us referred it to " Sjyirtllma,^^ which was then 

 supposed to include both opaque and transparent monothala- 

 mous shells, either discoidal or twisted f. In 1857 all these 

 together were spoken of as " the SpirilUnce [hyaline], Cornu- 

 sjpiroi [opaque], and their allies," common in the recent and 

 the fossil state, and as including the minute fossils from the 

 IVIagnesian Limestone that we have here to treat of (Ann. 

 Nat. Hist. ser. 2. vol. xix. p. 285, & note). Further distinc- 

 tions had been made by 1860, when the opaque forms were 

 subdivided — some left to Cornusjjira and others placed with 

 Trochammina^ the little Permian fossil being provisionally 

 referred to the latter (Quart. Journ. Geol. Soc. vol. xvi. p. 305, 

 note). A similar intimation of its alliance is given in Carpen- 

 ter's 'Introd. Foram.' (Ray Soc), 1862, p. 142, and in the 

 ' JMonograph of the Foraminifera of the Crag ' (Palteont. Soc), 

 1866, p. 26. Finally, one of the varieties of this protean 

 Microzoan is so much like a Miliola that one of us referred to 

 it, a few years back, as Miliola? jyusilla^. 



§11. Frequently this little fossil occurs as casts in the lime- 

 stone (as at Humbleton, near Sunderland), and most usually 

 as an oblong coil of white, calcareous, subcylindrical, wire- 

 like folds, with appreciable intervals, especially between the 

 larger, outer folds. A central, irregularly twisted, tubular 

 mass, of about -jV inch in diameter, is enclosed in eight or 

 nine outer folds ; these are flat or slightly concave on their 



• The last Part of this Series of Papers was inadvertently entitled 

 "Part X. (continued)" instead of ''Part XII." See Ann. Nat. Hist, 

 ser. 3. vol. xvi. p. 15. 



t In 1854 the discoidal forms alone were referred by one of us (in 

 Morris's 'Catal. Brit. Foss.' 2nd. edit. p. 42) to " Spirillina." 



X ' Svnopsis of the Geology of Durham and part of Northumberland,' 

 by K. Howse and J. W. Kirkby, p. 13. 8vo, Newcastle, 1863. 



