438 TUNICATE MOLLUSCS. 



During this period of existence, our mollusc therefore enjoys to a high degree the 

 characteristic faculties of a living being. It moves, and is brought in relation with the 

 external world by organs of the special senses. Now, however, comes a last metamor- 

 phosis, and this same Teredo loses its organs of motion and sensation, becoming a kind 

 of inert mass in which vegetative life replaces almost entirely the active spontaneity of 

 the animal." 



While we cannot but admire the painstaking research which has brought to light 

 these curious processes in the life of the Teredo, we must dissent from the opinion 

 expressed in the last paragraph. All animals are created to enjoy the life which the 

 divinely implanted instinct forces them to lead, and there is no reason whatever for 

 supposing that the Teredo when sunk in its burrow, without any apparent organs of sight 

 or hearing, is not enjoying its life as thoroughly as when it roamed the ocean in full 

 possession of both faculties. It seems to me that in speaking of the perfect Teredo as an 

 inert being, more like a vegetable than an animal, M. de Quatrefages loses sight of true 

 philosophy, and falls into the same error as the earlier naturalists, who wrote with 

 scornful compassion of the miserable lives led by the sloth, the mole, and the wood- 

 pecker. They fell into the mistake of judging all other beings by their own standard, and 

 knowing that to be forever buried underground like the mole, crawling among branches 

 like the sloth, or perpetually hammering at tree-trunks with their mouths like the wood- 

 pecker, would be a most wretched and painful life to themselves, hastily concluded that 

 the creatures above mentioned must be equally miserable under similar circumstances. 



It is, moreover, hardly in accordance with common sense that the animal should be 

 less happy in its perfect than in any preliminary stage of existence, inasmuch as then 

 only can it fully carry out the great law of nature. No one fancies that the butterfly is 

 less happy than the caterpillar, or the bee than the grub, simply because in these par- 

 ticular cases the elements of happiness are more palpable to human senses, or more 

 analogous to our own ideas upon the subject. We have now begun to learn the won- 

 drous powers of adaptation, whereby every living being is rendered happiest in its proper 

 place; and it surely is but philosophical to infer that whatever might be the case with 

 ourselves, who were not made to burrow in wood, the Teredo, which was created for 

 that express purpose, will enjoy its life like every other being. It is true that man would 

 be very wretched if deprived of eyes and ears, and compelled to spend his existence in 

 a hole just large enough to contain his body ; but he would not be more miserable than 

 the Teredo would be, if removed from its congenial tunnel and forced to live in a warm 

 drawing-room. " What is one man's food is another's poison ; " and the conditions which 

 would inflict unendurable torture upon one being, afford the only means by which another 

 can be made happy. We may as well pity the polar bear for the bitter cold of its native 

 land, or the tropical animals for the burning heat of their midday sun, as waste our 

 compassion upon the Teredo because it lives in a burrow beneath the waters. 



AN enormous species of this genus, called from its dimensions the GIANT TEREDO 

 ( Teredo gigantea ), has been found at Sumatra. This huge mollusc sometimes attains 

 the length of six feet, and a diameter of about three inches, but fortunately for timber, 

 does not make its habitation in that substance, contenting itself with boring into the 

 hardened mud of the sea-bed. The color of the shelly tube is pure white externally 

 and yellow within. On account of its mud or sand burrowing habits, the specific title 

 of arendria has been applied to this species. 



THE strange-looking objects that are represented in the accompanying illustration 

 have long perplexed systematic naturalists, and even now, although they have been the 

 subject of careful examination by accomplished zoologists, many parts of their economy 

 are enigmatical in the extreme. The order to which they belong is called by the name 

 of Tunicata, because the animals possess no shell, but are covered with an elastic tunic. 

 Some of them are transparent and really beautiful, while others are apparently little 

 more than shapeless masses of gelatinqus substance, studded with minute stones, 

 fragments of shells, and coarse sand, overgrown with seaweeds, and perforated by 

 certain bivalve molluscs. 



