TIIIC NAUTILUS.— FHOLADID.E. 



Tlic Anjonaul sailiiuj in the Open Sea. 



We may not woiiJer that this graceful but curious 

 animal attracted the attention and excited the admi- 

 ration of ancient naturalists, who were jirone to invest 

 it with a mythic interest and surround it with all the 

 ornaments of a luxuriant fancy. "The Nautilus 

 Polype," says Aristotle, " is of the nature of animals 

 which men call e.xtraordinary, being able to float on 

 the sea ; it raises itself from the depths of the waters, 

 with shell reversed and empty; when it has reached 

 the suiface re-adjusts its habitation. Between the 

 arms spreads a kind of tissue similar to that which 

 unites the toes of web-footed birds. When the wind 

 blows gently, it employs this tissue as a rudder, letting 

 it fafl into the water with the arms on each side. On 

 the approach of the least danger it fills its shell with 

 water, and sinks down into the deep." 



Oppian's account is still mure circumstantial : — 

 "Hiding itself in a concave shell, the Pompylius [a 

 name given to it by Pliny] can walk on land (!), but 

 can also rise to the surface of the water, the back of 

 its shell ujipermost, for fear tliat it should be filled. 

 The moment it perceives itself to be discovered, it 

 turns the shell and navigates it like a skilful seaman. 

 For this purpose it throws out two of its feet like 

 antenuce, between which is a thin membrane, extended 

 by the wiud like a sail, while two others, which touch 

 the water, guide, a.s with a rudder, the house, the ship, 

 and the animal. On the advent of danger, it quickly 

 folds up its antennae, its sail, its rudder, and dives; its 

 weight being increased by the quantity of water which 

 it admits into its shell. As we see a man who is 

 victor in the public games, with a crown encircling 

 his head, while vast crowds press around him, so has 

 the Pompylius a throng of ships ever following in its 

 track, whose crews no longer fear to quit the land. 

 fish, justly dear to mariners! thy presence heralds 

 soft propitious winds; tliou art the harbinger and the 

 usher of calm weather I" 



Oppian alludes in this passage to a superstition cur- 

 rent among the Pioujans, that it was a favourable omen 

 to meet the Nautilus. They regarded it as a kind of 

 tutelar divinity, who guided the seaman on his way, 

 and assured him of a fortunate voyage. 



The peculiar features of the Nautilus have been 

 observed by the Chinese, who call it the Boat-polyp. 

 According to Rumphius, its shell is highly valued by 

 the Hindoos, whose females consider it a superb orna- 

 ment. In their religious festivals the dancers carry it 

 ]iroudly aloft in the right band, holding it above tlie 

 head. To recommend it to the notice of modern 

 naturalists, however, it does not require any adven- 

 titious aid. No one can sec it sailing along the 

 tranquil waters like a fairy skilT, as our artist has 

 depicted it in the accompanying illustration, without 

 a transport of admiration. But we reserve our wonder 

 rather for Him who made it — for the power and 

 wisdom, almighty and infinite, which called it into 

 existence — than for the thing itself, however graceful 

 its appearance, and however curious its properties. 



It should be added, that opportunities of observing 

 the Nautilus are not easily obtained. It never comes 



near the shore. It is a timid and cautious creature, 

 which almost always prefers the vast solitudes of the 

 open sea. It seems to be gregarious in its habits, and 

 voyagers speak of it as living in families, some hun- 

 dreds of miles from the nearest land. It is only at 

 night, or as the sun withdraws its purple splendoiu', 

 that the Nautili gather together to enjoy their innocent 

 sports on the surface of a tranquil ocean. 



It enjoys, like other Cephalopods, the strange 

 faculty of changing colour under the influence of any 

 sudden impression ; blushing, or turning pale, and 

 through its transparent shell revealing the rapid 

 changes of its bod}'. 



Three species are at present recognized in our scien- 

 tific classifications : — the Arqonaula Argo, already 

 described ; the Argonauta tiiiercula, which is entirely 

 confined to the Indian Ocean: and the Argonauta 

 hallUint, which is occasionally met with in the Pacific 

 and the Atlantic Oceans. 



PHOLADID.^i:. 



The PholaclidcB form a family of lamellibranchiate 

 molluscs, remarkable for their boring habits. While 

 some of the species burrow in the sand, like the Solen, 

 others work out for themselves a dwelling-place in 

 timber and stone. Their mission in nature seems to 

 be the excavation of these strange retreats; and to 

 appear at their openings, or to sink into their depths, 

 makes up all the variations of their seemingly mono- 

 tonous existences. 



In this family we find the shell open at either 

 extremity; it is thin, white, of great hardness, and 

 sometimes furnished with accessory valves ; the two 

 principal valves are covered with calcareous pro- 

 tuberances, connected by fine transverse ridges, and 

 thus composing a kind of saw or rasp, which the 

 animal uses in its mining operations. 



The animal itself has a thick, white, elongated, 

 fleshy body, club shaped or vermiform ; its mouth 

 ejects a long tube traversed by two canals or syphons; 

 through one of which it absorbs the water necessary 

 for respiratory purposes, and through the other gets 

 rid of it. A short thick foot, acting like a sucker, 

 protrudes through an aperture in the mouth. 



"We lift one from its cavity," says Gosse, "all 

 helpless and unresisting, yet manifesting its indig- 

 nation at the untimely disturbance by successive 

 spasmodic contractions of these rough, yellow syphons, 

 each accompanied with a forcible jet cVcau, a polite 

 squirt of sea-water into our face; while at each 

 contraction in length the base swells out, tiU tho 

 compressed valves of the sharp shell threaten to 

 pierce through its substance." 



How the Pholades, or Plddochs, as they are vul- 

 garly' called on the British coast, contrive to excavate 

 the holes wherein, like true Troglodytes, they live, 

 has been a constant subject of dispute among natura- 

 lists. It was long asserted that the animal possessed 

 an excavating instrument, beset with hard silicious 

 particles ; but it is unquestionably true that no such 



