SPIRULA. 



TESTA univalvis, libera, concamerata, convoluta, 

 anfractibus paucis, disjunetis; septis siphunculo 

 perforato, marginibus integris. 



Animal Cephalopodum. 



Distinguished from Nautilus by the separation of the 

 volutions, and from Ammonites by their chambers not being 

 sinuated at the edge. This is a remarkable and elegant 

 little shell, whose animal is undoubtedly a Cephalopod in 

 a great measure covering the shell. It has been described 

 and figured by Peron and Lesueur in the Voyage de 

 Decouvertes aux terres Australes, vol. I. p. 45, pi. XXX. 

 f. 4. a. 4. b. 



Shell univalve, free, internal, (partly seen through the 

 posterior extremity of the animal,) convoluted, chambered ; 

 volutions few in number, separated ; the septum or wall 

 dividing each chamber perforated by a little siphon or 

 tube, which passes through the chambers without opening 

 into them; margins of the septa entire. 



Only one species of this Genus is at present known, 

 whi(;h is recent, and inhabits the Atlantic and Indian 

 Oceans. Its animal appears to be pelagic, and when 

 dead, the shells are found in abundance floating on the 

 surface of the water. They are also frequently thrown on 

 the shore. 



