SPECIES AND RANGE. 743 



The sexual dimorphism manifested by the shells of recent Nautilus has also been 

 observed among the much more numerous species which occur in the fossil state. For 

 example, it is shown in a striking manner in the figures of Nautilus bradfordensis Crick, 

 contained in an article by Mr G. C. Crick 1 , where he described and figured the shells of 

 eleven species of Nautilus taken from various zones in the Inferior Oolite of Dorsetshire, 

 of which no fewer than ten were registered as new to science. 



4. Species and Range. 



1855. Sowebby, G. B. Monograph of the genus Nautilus. Thesaurus Conchyliorum, 

 Vol. II. pp. 463 — 465. PI. xcvu. and xcvili. 



1855. Macdonald, J. D. On the anatomy of Nautilus umbilicatus compared with 

 that of Nautilus pompilius. Phil. Trans. 1855, pp. 277 — 288, 2 plates. 



1857. Gould, A. A. On the true Nautilus umbilicatus of Lister. P. Zool. Soc. 

 London, xxv. 1857, pp. 20, 21. 



1859. Bennett, G. Notes on the range of some species of Nautilus, on the mode 

 of capture, and on the use made of them as an article of food. P. Zool. Soc. London, 

 xxvii. 1859, pp. 226—229. 



[In this paper Bennett erroneously speaks of N. macromphalus as occurring in the 

 New Hebrides.] 



1860. Bennett, G. Gatherings of a Naturalist in Australasia. (London, J. Van 

 Voorst, p. 374.) 



1877. Bennett, G. Notes on the Pearly Nautilus [N. pompilius], Ann. Nat. Hist. 

 (4), Vol. xx. pp. 331—334. 



1896. VatssiERE, A. Etude sur l'organisation du Nautile (caracteres zoologiques, 

 dimorphisme sexuel, tentacules et spadice). Ann. Sci. Nat. (8), u. pp. 137 — 186. PL 16 — 19. 



[Includes critical examination of the radulae of N. pompilius and N. macromphalus ; 

 Vayssiere quotes D'Orbigny (1846, Dictionnaire universel d'hist. nat., Article "Nautile") 

 to the effect that N. pompilius occurs at the Nicobar Islands "dont les habitants fument 

 et boucanent sa chair."] 



1896. Willey, A. Zoological observations in the South Pacific. III. On some 

 variations in the shell of Nautikis, with description of a new variety. Quart. J. Micr. 

 Sc, xxxix. pp. 227—230, with figures on PL 13. 



1898. Willey, A. Some zoological results of a voyage to Melanesia during the 

 years 1894 — 1897. [N. umbilicatus.] P. Cambridge Philos. Soc, ix. p. 398. 



Hitherto it has only been found really practicable to differentiate the recent species 

 of Nautilus according to the character of the shell in the umbilical region, and from 

 this point of view four well-marked forms have been distinguished, namely, N. pompilius 

 Linn., with umbilicus concealed by a deposit of callus in the adult, N. stenomphalus 



1 G. C. Crick, 1898, " Descriptions of new or imperfectly known species of Nautilus from the Inferior 

 Oolite, preserved in the British Museum (Natural History)." P. Malac. Soc. London, Vol. in. pp. 117 — 139, 

 1898. Cf. also Buckman, S. S., and Bather, F. A., "Can the sexes in Ammonites be distinguished?" 

 Nat. Sci., Vol. iv., June 1894, p. 427. 



