SUB-FAMILY ROTALINiE. 199 



Messrs. Parker and Rupert Jones have been brought by a careful study and extended 

 comparison to regard as essentially distinct. Thus a new distribution of the entire group 

 becomes requisite, neither of our genera having the same value with any one of D'Orbigny's ; 

 and as the whole group constitutes an extremely natural series, of which there is much to 

 be said in common, it will be convenient to treat of such generalities under this head, ratlier 

 than to disperse them among the separate sections which will treat of the peculiarities of 

 individual genera. 



342. Hidorij. — Every systematist who has attended to such minute shells, has had his 

 notice attracted by examples of the Rotaline series. Thus tlie world-wide typical Rofalia 

 Beccarii and the tropical Calcarina Sjjevyleri were both described in Gmelin's edition of the 

 ' Systema Naturae' under the generic designation Nautilus. A large number of Rotaline 

 forms were described and figured in the great works of Soldani (c, ci), under the generic 

 designations Nautilus and Hanmonia ; many plates being devoted to the protean varieties of 

 the Mediterranean shell since known as Truiicatulbia variabilis. Boys and Walker (ix) 

 described as British species of Nautilus not only the N. Beccarii (of the common " reversed" 

 form of which they made a distinct species), but also N. lobatulus and N. umbilicatulus, which 

 are varieties of the form since generally known as Truncalulina lobatula. Montagu (lxv) 

 also enumerated N. Beccarii among British species ; but he gave the generic name Serpula 

 to two Truncatuline forms which we now place with T. variabilis and 1\ lobatula in our genus 

 Plaiiorbulina. The admirable work of Fichtel and Moll (xLv) contains numerous figures of 

 the varieties oi Nautilus (Calcarina) Sj^engleri ; they distinguished as N. repamlus the Rotaline 

 form which we now differentiate as the typical Pulvvnulina repanda, other varieties of which 

 they designated as N. sinuatus and N. auricula ; and they gave the name of N. farctus to the 

 Rotaline form which we shall ditferentiate as Planorbulina farcfa, another variety of which 

 they designated as N. tuberosus. The name Rotalites was first introduced by Lamarck (lvii), 

 who subsequently (lviii) modified it to Botalia ; and from that time it has met with general 

 acceptance amongst systematists, having been sometimes further modified into Rotaliiia. 

 Particular Rotaline forms were further distinguished by Lamarck (lviii and lix) under the 

 generic names Biscorbites, Biscorbula, and Puloitnilus, for the last of which he afterwards (lx) 

 substituted Placentula. Although neither of these names has been generally adopted 

 {Biscorbis having been only employed by Blainville and by some British conchologists), yet, 

 for reasons to be presently stated, Biscorbina and Pulvinulina will be employed in the present 

 work as generic designations. A fossil Rotaline form which occurs in the Upper Chalk of 

 Maestricht received from Lamarck the generic name Siderolites, under a total misapprehension 

 of its nature ; this name, although admitted by D'Orbigny, must now be dropped, since I shall 

 show that the type which was designated by it is only a variety of the long previously 

 known Nautilus (Calcarina) Spengleri. It was of course to be expected that Montfort should 

 institute many new genera for the varietal forms of this group ; and accordingly wo find the 

 names Cidarollus, Cortalus (?), Cibicides, Eponides, Stordus, and Polyxcnus, applied to as many 

 Rotalines ; whilst the name Tinoporus was conferred upon a peculiar type which he seems to 

 have been the first to distinguish from Nautilus (Calcarina) Speiit/leri. All these names have 

 long since been discarded as unnecessary synonymes ; but we shall revive the last, for reasons 

 which will be stated hereafter (^ 390). 



