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Originally appearing in Volume V24, Page 534 of the 1911 Encyclopedia Britannica.
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SEAHAM HARBOUR, a seaport and urban district, in the South-eastern parliamentary division of Durham, England, 6 m. S. of Sunderland by a branch of the North-Eastern railway. Pop. (1901) 10,163. The harbour was built (1828) by the third marquis of Londonderry to facilitate the export of coal from the mines on. his adjacent property. Besides the coal trade there are extensive bottle and chemical works. SEA-HORSE. Sea-horses (Hippocampina) are small marine fishes which, with pipe-fishes (Syngnathina), form the Lophobranchiate division of the suborder Thoracostei. The gills of the members of this group are not arranged in leaf-like series as in other fishes, but form a convex mass composed of small rounded lobes attached to the branchial arches, as shown in the accompanying figure (fig. I) of the head of a sea-horse, in which the Fio. i.—Gills of Hippocampus abdominalis. gill-cover has been pushed aside to show the interior of the gill-cavity. Sea-horses differ from pipe-fishes by having a prehensile and invariably finless tail; it is long, slender, tapering, quadrangular in a transverse section, and, like the rest of the body, encased in a dermal skeleton, which consists of horny segments, allowing of ventral, and in a less degree of lateral, but not of dorsal, flexion. The typical sea-horse (Hippocampus) can coil up a great portion of its tail, and firmly attach itself by it to the stems of sea-weeds or similar objects. The body is compressed and more or less elevated, and the head terminates in a long tubiform snout, at the end of which is the small mouth. The configuration of the fore part of the body, as well as the peculiar manner in which the head is joined to the neck-like part of the trunk, bears a striking resemblance to a horse's head. Sea-horses are bad swimmers and are unable to resist currents. With the aid of their single dorsal fin, which is placed about the middle of the fish's body and can be put into a rapid undulatory motion, they shift from time to time to some object near them, remaining stationary among vegetation or coral where they find the requisite amount of food and sufficient cover. Their coloration and the tubercles or spines on the head and body, sometimes with the addition of skinny flaps and filaments, closely resemble their surroundings, and constitute the means by which these defence-less creatures escape detection by their enemies. These protective structures are most developed in the Australian genus Phyllopteryx, one of the most singular types of littoral fishes. Sea-horses belong to the tropics and do not extend so far north as pipe-fishes. They are abundant at suitable localities, chiefly on the coral-banks of the Indoo-Pacific Ocean. Some forty species are known, of which the majority belong to the genus Hippocampus proper. They vary from 2 to 12 in. in length; but in China and Australia a genus (Solenognathus) occurs, the species of which attain to a length of nearly 2 ft.; they, however, in form resemble pipe-fishes rather than sea-horses. The species which may be sometimes seen in European aquaria is Hippocam pus antiquorum, common in the Mediterranean and on the coasts of Portugal and France. It is rare on the south coast of England, but it has often been captured on the Essex coast. About 1885, according to Dr J. Murie, two Leigh fishermen when shrimping at Harwich during the summer season succeeded in procuring altogether between too and 120 specimens. The food of the sea-horses consists probably of very small invertebrates and the fry of other fishes. Like the other Lophobranchiates, they take great care of their progeny. The male Hippocampus carries the ova in a sac on the lower side of the tail, in which they are hatched; in the other genera no closed pouch is developed, and the ova are embedded in the soft and thickened integument of either the abdomen or the tail. All that is known of the habits of these interesting fishes will be found summarized in a valuable paper by T. Gill, " The Life History of the Sea-Horses (Hippocampids)," in Proc. U.S. Nat. Mus. xxviii. (1905), p. 8o5. SEA-KALE, Crambe maritima, a hardy perennial, a member of the natural order Cruciferae, which grows wild along the coasts of England, of Ireland and of the Scottish lowlands, along the western coasts of Europe, and on the Baltic, reappearing on the Black Sea. In cultivation sea-kale prefers a light dry soil, and when manure is necessary it should consist of sea-weed or well-rotted dung; or a dressing of salt or of nitrate of soda may be given. When raised from seeds, they should be sown in March or April in rows t ft. asunder, the plants being thinned to 6 in. apart. In the following March these should be planted out in trenched well-prepared ground, 2 ft. asunder, in rows 2r to 3 ft. apart. The top with the crown buds should be cut off before planting to prevent them from running to seed. In the spring of the second year the young shoots if blanched will be fit for use, and therefore the summer growth should be promoted by the use of water and liquid manure. Tolerably blanched stalks may be produced by plants only nine months old from the seed, and after two summers seedling plants will have acquired sufficient strength for general cropping. The seeds, instead of being sown in rows and transplanted,may be deposited in patches of three or four together, where they are to remain. In the autumn, after the leaves have been cleared off, the ground should be forked up, and 6 or 8 inches' depth of leaves or of light sandy soil laid over the plants, by either of which means they will be blanched, though not forced. The blanched sprouts should be cut for use whilst they are crisp, compact and from 3 to 6 in. in length, the stem being cut quite down to the base. Sea-kale beds may be made from cuttings of the roots of very healthy plants, the extremities of the roots, technically called " thongs," being best adapted for this purpose. They should be taken up in autumn, cut into lengths of about 4 in., and laid in a heap of sand or earth till spring, when they should be planted out tike the seedlings. Forcing.—Sea-kale may be forced in the open beds by the aid of sea-kale pots or covers, which are contracted a little at top, with a movable lid. One of the ,earthenware covers, or an inverted flower-pot, is placed over each plant, or each patch of plants, and leaves of trees are closely packed round the pots, and raised to about t ft. above them. When fermentation commences, the temperature within should not exceed 6o° F. If the crowns are thus covered up by about the end of October, the crop may be cut by about the third week of December, and by starting a batch at various times a supply may be kept up till the middle of May. Strong plants may also be taken up and planted on hotbeds, the sashes being kept covered close; or they may be set thickly in boxes as recommended for rhubarb, and placed in any heated structure, or in the mushroom house; but, to have the shoots crisp and tender as well as blanched, light must be completely excluded. Besides the common purple-leaved, there is a green-leaved sort, which is said to blanch better.
End of Article: SEAHAM HARBOUR

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