86 



MANUAL OF THE MOLLUSCA. 



for lia\dng taldiig in all tlieir tentacles, tliey upset tlieii- boat, and so retmii to 

 the bottom." 



Fig. 44. Nautilus expanded.* 



Distr., 2 or 4 sp. Cliinese seas, Indian ocean, Persian gulf. 



Fossil, about 100 sp. In all strata, S. and N. America (Chile). Europe, 

 India (Pondicheny) . 



Sub-genus. Aturia (Bronn), = Megasiphonia D'Orb. 



Ti/pe, N. zic-zac Sby. PL II., fig. 12, London clay, Highgate. 



Shell, sutures, T\ith a deep lateral lobe ; siphunde neai'ly internal, large, 

 continuous, resembling a succession of fimuels. 



Fossil, 4 sp. Eocene, N. America, Europe, India. 



Sub-genus ? Discites, McCoy. WJiirls all exposed ; the la«t chamber 

 sometimes produced. L. silm-iau. — Cai'b : limestone. 



Tenmocheilus, INIcCoy. Founded on the carinated sp. of the Garb, lime- 

 stone. 



Crgptoceras, D'Orb. Founded on N. dorscdis Phil, and one other spedea, 

 in which tlie siphuncle is neaily external. 



* Ideal representation of the nautilus, when expanded, by Professor Lov6n, vrbo 

 appears to have taken the details from M. Valenciennes memoir in the Archives da 

 Museum, vol. 2, p. 257. /;, hood, s, siphon. It is just possible, that when the 

 nautilus issues from its shell, the gas contained in the last, incomplete, air-chamber, 

 may expand ; but this could not happen under any great pressure of water. 



i 



