540 Transactions of the Society. 



mens it is easy to select a series linking all the published species 

 together. Haeusler appears to have formed the same opinion from 

 the study of liis fossil specimens, for he refers repeatedly to the 

 variability and inter-relationship of tlie species. 

 We therefore propose : — 



1. To retain the earliest described and figured species, 7\ papil- 

 lata Brady, as the type of the genus, and to include under this 

 specific name all Thurammiuc'B hitherto described and figured 

 under various specific names. 



2. Where' for taxonomic reasons further classification is re- 

 quired, to utilize already published specific names in a purely 

 varietal sense. 



3. To abandon certain specific names which are of no value 

 even for varietal classification. 



4. To form certain new varietal distinctions for groups which 

 have not hitherto been described or adequately separated from 

 other groups. 



Before proceeding with our survey it will be useful to indicate 

 a few stages in the life-history of Thurammina ascertained from 

 the examination of numerous sections and balsam-mounted speci- 

 mens, as the observations throw considerable light on the subse- 

 quent appearance of the individuals and their development, and 

 will therefore assist us in our classification, 



Thurammina, like all the Arenacea, is a benthic organism. 

 Although from its spherical form, isomorphous with Orhulina and 

 many Eadiolaria, it might be surmised that it was suited for a 

 pelagic existence, tliere are no records of its occurrence in this 

 condition even in those early stages before it acquires the arenaceous 

 investment wliich marks the mature stage of growth, and which of 

 course could only be secreted by a benthic organism. But the 

 initial stages of the organism are passed in a chitinous envelope, 

 and we consider it not improbable that a more careful examina- 

 tion of tow-nettings from suitable localities may result in the 

 discovery of pelagic individuals in the chitinous condition which, 

 as we shall demonstrate, is frequently retained until the organism 

 has attained its full development in size, and has acquired the 

 characteristic oral papillae. 



On sectioning a number of specimens of Thurammina, and 

 especially in the case of T. eariosa Flint, individuals will be found 

 in which the central cavity contains a number of "gemmules," or 

 minute bodies of a spherical or sometimes of a pointed oval shape 

 and dark shining appearance, loosely aggregated together or attached 

 to the inner wall of the shell (PI. XXIX, fig. 8). Other specimens 

 will be found with the cavity more or less filled with a reddish 

 mass, like raspberry jam, consisting of similar gemmules, but of 

 larger size (PI. XXIX, figs. 9, 10). These gemmules are quite 

 different in appearance from the dark protoplasm with metaplastic 



