GENUS NUMMULINA. 263 



452. The commencement of a more exact knowledge of this type may be considered to 

 date from Scheuchzcr ; who, at the beginning of the last century, gave a description of the 

 examples of it occurring in Switzerland, which, as far as it goes, is very exact,*' regarding 

 them as a new type of Cornu Ammonis. Among succeeding naturalists, however, a great 

 variety of notions prevailed as to their essential character ; all which will be found elaborately 

 set forth in the admirable monograph of MM. D'Archiac and Haime (i). It will be suffi- 

 cient here to state that Lancisi (1719), who described them under the name of iiuinmi lapidci, 

 supposed them to be the madreporiform plates of marine Echinites ; whilst Buckmann, who 

 wrote specially on the lapis iminismaUs of Transylvania (1727), considered them to be bivalve 

 Mollusks ; and Bourguet in his Treatise on Petrifactions (1729), maintained that they were 

 the opercula of Ammonites. Notwithstanding that Guettard, in a special memoir devoted 

 to them (1770), pointed out that they have neither the large open mouth nor the siphon of 

 those chambered shells, they were ranked by Plancus (lxxxiii), Gualtieri (li), Soldani (c), 

 and most writers of the latter half of the eighteenth century (sometimes under the name of 

 Helicifes and Camerina, the latter given by Bruguicre), among Nautili or Ammonites. This 

 erroneous view was adopted even by Cuvier, who in his first systematic classification 

 ('Tableau Elcmentaire,' 1798), ranged this type under the name of Camerinu after OrthorerK- 

 tites, at the end of his series of Cephalopod Mollusks ; and also by Lamarck, by whom the 

 genus NummuUtes was first created (lvii). The first good descriptions of specific forms were 

 those of Bruguiere ('Encyclopedic Muthodique,' 1792), who distinguished four species of his 

 genus Cdiiierinii, amongst them the C. lievif/ala ; and his descriptions of these were followed 

 by Lamarck. 



453. The greatest confusion prevailed at the commencement of the nineteenth century, 

 in regard to the objects ranked together under the several designations applied to Nummulites ; 

 and this confusion is especially apparent in the memoir of Fortis (' Mem. pour servir a I'Hist. 

 Nat. de ITtalie,' 1 802), who introduced the new name Discolitlms for the bodies previously known 

 under the names of " pierres lenticulaires, numismales, frumentaires, helicites, et dernierement 

 caracrines \' and ranged under it the very different types which are now distinguished 

 as Nunimidbia, OrhUolite-'<, FaJjiilaria, Alveolhia, Orbiloides, and Ccdcarina. Towards clearing 

 up this confusion an important step was made by the separation effected by Lamarck (lvhi, 

 1804, 1806), between the Nummuline and the Orbitoline types; the genera Nummulites and 

 Lenticulltes (the latter founded on differences which have since proved not to be of generic 

 value) being retained among the chambered Cephalopods, whilst OrbitoUfes (under which 

 designation were ranked some of the forms now distinguished as Orbifoides) was referred to 

 the group of Zoophytes. As an illustration of the vagueness of the opinions yet prevalent on 

 the nature of these bodies, it is worthwhile to mention that Deluc (1802) and De Roissy 

 (1805) considered them to be altog-ether internal shells, analogous to the so-called "bone" of 

 the cuttle-fish ; whilst Dumcril in his ' Zoologie Analytique' (1806) likened them to the disks 

 of Forpitn, and ranged them among the Medusas. De Montfort (lxvii), according to his 

 wont, erected certain species of Nummulites into the new genera Lycopliris, llotalites, and 

 E(/eo)i ; names which are now entirely discarded. Subsequently (lx) Lamarck came to 



* ' Specimen litliographiae Helveticse curiosse,' &c., Tiguri, 1702. 



