808 FOOD ; MIGRATION ; PROPAGATION. 



the shell), but that they retain many primitive features such as the crop, the septum 

 between the renal sacs, the paired oviducts. 



20. Food; Migration; Propagation. 



The specimen of Nautilus which was dissected by Owen contained fragments of 

 triturated Crustacea in its stomach and crop, and this would seem to constitute its staple 

 food-supply since prawns and crabs abound on the nautiline terrains. 



As mentioned in a previous chapter any kind of animal bait will tempt Nautilus, 

 and after a full meal the crop is found to be gorged to repletion. 



In order to be in a position to form a just estimate of the value of the various 

 accounts and legends concerning the habits of Nautilus several facts require special 

 consideration. In the first place Owen drew attention to the circumstance that whereas 

 two kinds of Nautili are referred to by Aristotle, only one kind is mentioned by Pliny. 

 In his Thesaurus Gonchyliorum, Sowerby (1855) took care to note particularly that 

 the Pearly Nautilus is not the Nautilus of Pliny, which is Argonauta or the Paper 

 Nautilus, so-called on account of the thin, white, delicate structure of its peculiar shell. 



No doubt many of the fantastic ideas concerning our Nautilus, more especially such 

 as possess the popular mind, owe their origin to a simple confusion between the Pearly 

 or, as we may picturesquely term it, Aristotle's Nautilus and the Paper or Pliny's Nautilus. 

 That this is the case is indicated in a convincing manner by the identity of some of 

 the myths which have been related in connection with both species 1 . 



It is also desirable to remember that Nautilus obviously draws its supplies of food 

 from the bottom of the sea, it is a ground-feeder, while Argonauta, according to available 

 evidence, is a pelagic feeder. 



When Nautilus has been taken, as a great rarity, at the surface of the sea, it has 

 generally, if not always, been found that the specimen was in a more or less moribund 

 condition. At the same time, with its known faculty for swimming and migration in 

 some places into quite shallow water a few fathoms only in depth, it is quite conceivable 

 that an individual specimen might occasionally wander away from its home and arrive 

 at the surface, but there is no evidence that this is a regular practice. 



In his " Notes by a Naturalist on H.M.S. Challenger," Moseley also gives it as his 

 opinion that " it is probably a mistake to suppose that it ever comes to the surface 

 voluntarily to swim about." 



Moreover only single individuals have ever been seen at the surface and then in the 

 daytime 2 , but the evidence of the traps goes to show that Nautilus is a gregarious 

 animal and nocturnal in its habits. It repairs in shoals at night to its shrimping 

 grounds, but I suspect that it breeds in deep water or in inaccessible submarine gullies. 



1 On the subject of the legendary accounts of the habits of Argonauta, the following interesting paper 

 may be consulted : — " Observation d'un Argonaute de la Mediterranee," by H. de Lacaze-Duthiers, Arch. Zool. 

 Exper. (2) x. 1892, pp. 37 — 50, with figure of the animal in swimming attitude on p. 41. 



2 E.g. Saville-Kent, W., "Preliminary observations in connection with the surveying cruise of 



H.M.S. Myrmidon at Port Darwin and Cambridge Gulf." P. R. Soc. Queensland, VI. p. 229, 1888. 



