IX. often mingled and often alternating, we learn at last LETTER to prefer those milder and more certain or enduring pleasures which calmly sooth us, to the bustle, the labour, and the excitements, that engage and animate our youth and maturer strength. Agitation and emotion at length lose their charm: they disturb more than they amuse us. As age advances to its sober evening, we perceive and appreciate the value of conscious life without pain; of sedate tranquillity; of reposing, yet not inactive, thought; of sensibility without perturbation; of patient hope; of resting moveability; of sensations that please, but do not agitate; of intellectual rumination; and of those solemn aspirations of sacred foresight, of prospective gratitude, and of humble reliance on the great mediatorial Benefactor, which close our mortal days with true dignity, and make even dissolution an inestimable blessing.". 67 Among the living creatures in the waters, are the TESTACEOUS and CRUSTACEOUS classes. The first are remarkable for the softness of their bodies, the continuity of their parts, the simplicity of their mouth, and the permanency of their attachment to their calcareous dwellings. Their shells are principally composed of carbonate of lime, with a small portion of animal matter. They are divided into three arrangements: the BIVALVES, including Oysters, Cockles, Muscles, Scallops, &c.; the UNIVALVES, as Periwinkles, Limpets, Welks, and Snails; and the MULTIVALVES. Bosc has classified these under several subdivisions, in his Hist. Nat. des Coquilles, in the Dict. Naturelle. In his system, the arrangement is more methodical, and the genera more definite, than in the Linnæan System. The Supplemeat of the Ed. Encycl. art. Conchology, details the classification of Bosc. Conchology comprises the shells which protect the Molluscous Animals. Ib. The CRUSTACEOUS, have a fibrous texture, articulated members, complicated organs of mastication, and at stated periods renew their coverings. Their shells contain phosphate of lime. Suppl. Ed. Encyc. p. 284. X. LETTER X. ON THE NATURE AND PHENOMENA OF THE MENTAL LETTER THE habits of Fishes are too little known for us to form sufficient ideas of the extent and degree of the mental faculty, which accompanies their living principle. The similarity of their brain to that of birds was remarked by one of our distinguished Anatomists of that grand function of our present mode of existence.' Their organs of sense resemble ours in the principle of their construction, with particular modifications to suit them to the watery medium in which they live.2 That they possess and exercise volition, many show. The two Sword Fishes who plunged their · 1 Dr. Th. Willis. As he had traced many resemblances between the brain of Man and that of quadrupeds, so he remarks of Birds and Fishes, Both these species of animals, coetaneous, and as it were twins at their creation, have their affinity in nothing more strongly than in the fabrication of the brain.' He proceeds to detail the similarities. Cereb. Anat. 67-76. The parts wanting in the one, are absent in the other. The additional peculiarities are exhibited by both. ... 2 Borelli examined the optic nerves of the Sword Fish, Thunny, and others; and disputed with Eustachius and others on their structure: contending, that they were cross barred and complicated like cloth, and not longitudinal fibres. Lett. in Malph. Op. v. 2, p. 1–7, The optic nerves intercussate in them, as in animals. The medulla oblongata is exactly analogous to that of birds; fitting the one to swim in the sea, and the other for that flight in the air which may be called an aërial natation. Willis, 75. Their cerebellum resembles that of the more perfect animals. 76. Casserius Placentinus ascribed olfactory nerves to them. Ib. 3 X. beaks into the ships they pursued, apparently sup- LETTER posing them to be Whales, or some analogous substance, exhibited a vigorous determination of their will to their own perdition. Yet, tho mistaken in the object, the blow was not ill judged, nor the force with which it was given; for this would have buried their snout so far in a Whale, as to have enabled them to have extracted the nutritive matter they sought by the action, before the Whale could have loosened its wounded body from their attack. To mistake the keel of a vessel for the animal, was not a greater error than a seaman's mistaking a Whale for an island, or a fog-bank for a real shore, which has been repeatedly done.* The Fish which climbs trees displays an equal exertion of peculiar will, tho its exact intention is not known, beyond the general idea that it is seeking for food, or something agreeable to its perception." The Salmon exhibits a remarkable instance of determined effort to effect a rational purpose, in the extraordinary 3 See before, Note 29, p. 292. The Whale endeavours to strike its assailant with its tail; of which one blow would destroy him. The Sword Fish, by great agility, avoids the descending ruin, and, bounding in the air, again falls upon the Whale. Milton has noticed one of these illusions 'Him haply slumb'ring on the Norway foam Par. Lost. B. 1. The Perca Scandens, which inhabits rivulets in Tranquebar; about a palm long. By the means of the spines of its gill-covers, and the spinous rays of its other fins, it crawls up trees. Linn. Trans. v. 3, p. 62..... Lieut. Dalderff saw it ascending a palm growing near a pool of water; it had got up five feet when observed. It was very tenacious of life, for it moved about on dry land many hours after it was taken. Ib..... Dr. Shaw calls it the Climbing Sparus. G. Zool. vol. 4, p. 475. X. 6 LETTER leaps which it makes to surmount cataracts or other obstacles, which impede its progress as it ascends a river. This requires not only will, but correct perception and judgment, as its muscular exertion must be regulated by the extent and nature of the hindrance which it meets with, and by a perception of the height to which its spring must reach. Other Fish can make such elevating starts when they chuse." The several species of Flying Fish display, in like manner, voluntary exertions on emergencies of danger, in order to escape it, and the idea how they can do so: a spontaneous motion for a reasonable purpose, at the proper moment, and continued as long as the necessity lasts, or the ability to perform it remains.R 7 • Mr. Pennant watched them at Port Aberglaslyn, where they had to pass a perpendicular fall. They sprang up quite straight, and with a tremulous motion. They do not always succeed in their first leap, and in that case repeat it, if they can, till they have cleared the difficulty. The leap is sometimes seven or eight feet. Brit. Zool. v. 9, p. 284. 'On the River Liffey, in Ireland, there is a cataract about 19 feet high, up which these fish leap. They frequently fall back many times before they surmount it.' Biog. vol. 3, p. 270. Bing. An. 'The Trout leaps several feet out of the water. T. Linn. 847. And the Trichiurus of South America, often leaps into boats as they pass by. Ib. 712. The Scorpœna Volitans, in the fresh waters of Amboyna and Japan, less than the River Perch, thus raises and suspends itself for a time, when pursued. T. Linn. 757..... So the Trigla Volitans of the Mediterranean and Asiatic Seas, flies out of the water in every direction when endangered. Ib. 834.... The Exocœtus Volitans is the most celebrated for this exertion. It is done in all by the pectoral fins; but the flight can be supported only while they are wet. Captain Tobin watched them about Otaheite. They use their tail to supply their pectoral wings with the needed moisture. He frequently saw the Dolphins and Bonitos in pursuit of them; but none could go beyond 100 yards without dipping in water for a fresh supply of wet. Its length is from 12 to 15 inches. Penn, Br. Zool. v. 3, p. 333. Wood, Zool. 2, p. 187. . . . . They are sometimes in danger from sea-birds while in the air; but this coincidence of their presence X. All the active mind which both hare and hounds LETTER display in a rural chace, was exhibited in that accidental pursuit of these fishes by the Dolphin, which Captain Basil Hall has so interestingly described.o The periodical migrations of so many tribes, for the purpose of fecundating and depositing their eggs, display a mental instinct in rational, persevering and efficacious operation. The same combination of action and judgment appears in the Fish that crawls on land in search of water; 10 and in the night journeys of presence cannot very often occur. The casual incident has been dolorously magnified into an habitual circumstance, and the Fish supposed therefore to lead a miserable life. It is most probable that, having the power of the aërial excursion, it often uses it for its own amusement. • About a dozen Flying Fish rose out of the water, and skimmed away to windward at the height of ten or twelve feet. A large Dolphin that was keeping in company at the depth of two fathoms, and glistening beautifully in the sun, no sooner saw them, than he turned his head toward them, and darting to the surface, leaped from the water with a velocity little short of a cannon ball. The length of his first spring was 10 yards; but they kept ahead of him. After he fell, we could see him gliding thro the water for a moment; then he rose, and shot forward with a still greater velocity, and to a still greater distance. In this manner he pursued them, while his brilliant coat sparkled and flashed in the sun quite splendidly. The Flying Fish, thus hotly pursued, dropped into the sea, to set off again in a fresh and more vigorous flight, but took a different direction, implying that they had detected their enemy, who was now gaining upon them. His pace was two or three times as swift as theirs. Whenever they varied their flight in the smallest degree, he lost not the tenth part of a second in shaping a new course, so as to cut off the space; while they in a manner, not unlike that of a hare, doubled more than once upon their pursuer. As they became exhausted, he seemed so to arrange his springs, that he contrived to fall at the end of each just under the spot where they were about to drop. We saw them one after another drop into his jaws as they lighted on the water, or were snapped up immediately afterwards.' Capt. Hall. Fragm. of Voy. 2d. Series. 10 The Callichthis Silurus 'inhabits small running streams of Europe, and when these are dried up, crawls across meadows in search x 3 |