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 RAY 221 Systems" (1861); in conjunction with his brother Henry and Sir J. G. Wilkinson, an annotated translation of " Herodotus" (4 vols., 1858-'60); and "Historical Illustrations of the Old Testament" (1871). His most cele- brated works are "The Five Great Monarchies of the Ancient Eastern World, or the History, Geography, and Antiquities of Chaldraa, As- syria, Babylonia, Media, and Persia" (4 vols., 1862-'7; 2d ed., republished in New York, 1871), "A Manual of Ancient History" (1869), and u The Sixth Great Oriental Monarchy, or the Geography, the History, and the Antiqui- ties of Parthia " (1873). RAY, the name of the plagiostome, chondrop- terygian, or cartilaginous fishes of the suborder raiiw, popularly called skates. The numerous families are characterized by great flatness and width of the body, the latter arising princi- pally from the extreme expansion of the pec- toral fins ; the skull is flat, the upper wall gen- erally membranous, and movably articulated, as in sharks, by two condyles and an interve- ning space with the spine ; anteriorly the head ends in a tapering cartilage which supports the snout ; spout holes or spiracles for respiration and eyes on the dorsal aspect, the latter with- out lids or with an upper adherent one ; on the ventral surface are five slit-like gill openings, before the ventrals and under the pectorals; the scapular arch is complete above and be- low, supporting the long, jointed, cartilaginous rays of the pectorals; between this and the pelvic arch, supporting the ventral, lie the ab- dominal viscera, and between it and the nar- row skull are the branchial apparatus and the vascular centres. The spiracles are openings by which the water may pass from the upper surface of the head into the mouth cavity, and are found in perfection only in those species which live upon the bottom; the eyes being above, and the fins feeble, they seek their prey by the sense of touch in the snout, stirring up the mud and sand while feeding; their gills would thus be injured by gritty materials were the water taken in from below by the mouth ; in the rays the comparatively pure water enters from above by the spiracles, and passes out at the branchial openings, or vice versa. The de- velopment of these openings is in direct pro- portion to that of the sense of smell, and in inverse proportion to that of sight. (See " Pro- ceedings of the Boston Society of Natural His- tory," vol. xvii., November, 1874.) In the tor- pedoes the cellular galvanic batteries occupy the spaces between the skull and the pectorals ; and a homologous rudimentary apparatus has been found in the tail of common skates, show- ing the adherence to a general plan of structure irrespective of function. The tail in some is fleshy and tapering, in others slender and car- tilaginous, in others elongated like a whip lash, and in others armed with lancet-shaped spines on the upper surface, making a very formida- ble weapon. The gills consist of membranous folds on plane surfaces, and the arterial bulb has from two to five transverse rows of semi- lunar valves. The reproductive secreting or- gans are compact and oblong, the efferent tubes communicating with the ureters and ending in a rudimentary organ in the cloaca ; the claspers are present in the males, as appendages to the posterior edge of the anal fin, fissured toward the end, leading to a blind subcutaneous sac well lubricated with mucus and the secretion of a glandular body ; the ovaria are compara- tively small, and the ova are larger and fewer than in common fishes, and more as in birds ; most of the genera are viviparous, but some of the genus raia are oviparous. The claspers are not mere organs of prehension ; they may be so rotated as to bring an opening in them oppo- site to the spermatic duct, and may, according to Agassiz (" Proceedings of the Boston Soci- ety of Natural History," vol. vi., p. 377, May, 1858), be introduced into the oviducts, and reach the glands there situated for the forma- tion of the egg case. They are true intromit- tent or copulatory organs. The egg cases of the skate are often seen on our beaches after a storm; they are quadrangular, about two inches by one, brown and leathery, each corner pro- longed into a tubular process ; they look some- what like pillow cases, and are often called sailors' purses and skates' barrows. The young within the egg has no investing membrane, and the yolk seems to bear no relation in size to that of the embryo ; water for respiration is admitted and ejected through the corner pro- longations, and the young fish escapes through a transverse fissure at one end. The horny egg case may be formed in each oviduct, and is surrounded by a glandular enlargement which secretes its materials ; it is formed before the egg descends into it, in the shape of a pocket open above for the reception of the egg, which must be impregnated in the ovary, contrary to the usual order of things, in which the yolk is enclosed before the shell is formed; as the eggs are found to be of different sizes and va- rious degrees of development in the ovary, it is probable that several years are required for their maturity; these peculiarities show the propriety of placing the skates (with the sharks forming the division of selachians of Aristotle and Agassiz) in a class by themselves. The teeth of the rays are generally tubercular, in close quincunx order like a mosaic pavement. Disgusting as is the form of the rays, their flesh is esteemed a delicacy in England and France, though it is rarely eaten in America except by those of European origin ; it is tough when first caught, but becomes tender by being kept several days ; with us it is most commonly used as bait for lobster pots, or for manure. Of the families of rays, the pristidce and torpedinidce will be described under SAWFISH and TORPEDO respectively ; the cephalopteridce have been no ticed under DEVIL FISH. The family rhinoba- tidce, are intermediate between sharks and rays, having the form of body, position of fins, thick, fleshy tail, and smallness of pectorals of the