463 



MONOGRAPH OF THE GENUS 

 NAUTILUS. 



Char. Gen. Molluscum cephalopodum. Testa univalvis, libera, 

 siiborbicularis, convoluta, concamerata ; anfractibus contiguis; 

 septis transversis, extus concavis, siphunculo perforato, margi- 

 nibus integris : apertura amplissima. 



By the common consent of the more modem naturalists, this 

 genus retains the name of Nautilus, although it is not very 

 nearly related to the Nautilus of Pliny, which is called Argonanta 

 by the moderns, to which the commonly received and elegantly 

 embodied fiction 



" Learn of the little Nautilus to sail" 



of right belongs, and has no reference whatever to the present 

 genus. 



Pew are the recent species of Nautilus as yet known, five being 

 the utmost, of which one may be only a sexual variation of the 

 common N. Pompilins, and one other has only very lately been 

 discovered. Of fossil species there are many, belonging to most 

 of the geological series, from the carboniferous limestone upwards. 

 We believe that all the fossil species are distinct from the recent, 

 more particularly we are convinced that this is the case with the 

 species found at Dax, whose siphon is so very remarkably dispro- 

 portionate.^ 



1. Nautilus Pompilius (pi. xcvii. f. 1., and pi. xcviii. f. 6), 

 Linyi. 



Testa suborbicularis, subdepressa, pallescens, postice ferrugiueo 

 radiatim multistrigata, strigis ad centrum continuis, supra dorsum 

 numerosioribus, contiguis ; apertura oblongo-cordata, angustiori ; 

 umbilico clauso. 



This, which is by far the commonest species, is somewhat 



* In this opinion we are supported by M. Basterot, who has pointed out the dis- 

 tinffuishinar characters, and names the fossil, N. Atiiri. 



