Page:The American Cyclopædia (1879) Volume VIII.djvu/36

 28 GLASS SNAKE the tongue arrow-shaped, triangularly grooved in front, free in its anterior extremity, on which the papillae are granular; the nostrils are near the snout, lateral, opening upward; the eyes are small, protected by two movable unequal lids ; there are several rows of short conical teeth, about 36 in number, on the roof of the mouth, chiefly on the pterygoid bones ; the intermaxillary teeth are conical, the max- illary simple and nearly cylindrical, about 40 in all above and 36 below ; the external ear is a small oval opening just behind the angle of the mouth. There is no distinct neck; the body is elongated and snake-like, covered with small, smooth, slightly imbricated scales, dis- posed in circles around the body, about 120 in number ; there is no vestige of anterior or pos- terior limbs externally, and only their rudiments internally ; there is a deep groove separating the sides of the body from the abdomen, most visible during respiration, and which doubtless affords the free movements of the ends of the ribs necessary for progression. The tail forms at least two thirds of the total length, round, and tapering gradually to the tip, covered with about 140 rings of scales. Though the shape of this reptile is snake-like, the movable lids, external auditory openings, less movable verte- brae, less extensile tongue, rudimentary ster- num, and above all the consolidation of the bones of the skull and jaws, sufficiently show its saurian affinities. The length varies from 2 to 3 ft. The head above is mottled with black and green, with a yellowish tinge on the jaws ; the body and tail above are marked with longitudinal and transverse lines of black, green, and yellow, each scale marked with these three colors; the under surface is yel- lowish, brightest on the abdomen ; some slight varieties of color are described. It is found on the Atlantic coast from southern Virginia to Florida, and as far west as the Mississippi, Mis- souri, and Ohio rivers ; it has been seen west of the Alleghanies as far north as Michigan. From the smallness of its gape it cannot de- stroy and swallow large prey, like the serpents ; it cannot climb nor swim, but passes its life on the surface of dry places or in natural cavities in the ground, living principally on mollusks, insects, annelids, and other small animals, and perhaps also partly on vegetable food like the sweet potato. It can move with considerable speed, and is taken uninjured with difficulty on account of the ease with which the joints of the tail are separated; the name of glass snake was given on account of this extreme fragility. The breaking of the tail into small pieces in this and in some scincoid reptiles seems to be the result of a reflex action in the spinal cord, as an irritation of this nervous cen- tre will cause a separation even after the tail is divided from the body. Dr. Burnett (" Pro- ceedings of the Boston Society of Natural His- tory," vol. iv., p. 223) ascertained that the cau- dal muscles in this reptile do not pass from one vertebra to another, but that a portion are in- GLASS SPONGE serted into the skin, while others terminate mid- way between one vertebra and the next, dove- tailed as it were between the fibres sent from that vertebra, and attached to them only by the myolemma; so that there is no rupture of muscular fibres, but only a separation of one layer of muscles from the adjoining one, when the tail of the animal is broken ; the detached portion is said to be reproduced in a year. The glass snake in its anatomical peculiarities resem- bles the chalcidian amphisbaena and the scin- coid blindworm (anguis fragilis). GLASS SPONGE, or Glass Rope, a silicious sponge of the genus hyalonema (Gray) ; the name may also be properly applied to other allied genera, and especially to the euplectella, which will be described under VENUS'S FLOWER-BASKET. This sponge was first described and named by Dr. J. E. Gray, of the British museum, in 1835 ; he regarded it as a coral allied to the sea fans (gorgonia), an opinion to which he still adheres, against what seems to be an overwhelming mass of evidence. As usually seen, this sponge consists of a loosely twisted bundle of glassy threads, diverging at one end and converging at fhe other, which is more or less covered with a brown crust, studded with wart-like cylin- drical elevations, terminating in radiating ridges. The threads are mainly composed of silex, and are shining, translucent, and very flexible ; the fascicle varies from 12 to 20 in. in length, and is about half an inch thick, the threads ranging from the size of a bristle to that of a knitting needle. The wart-like elevations are generally regarded as polyps, of the genus palythoa, con- tinuous throughout the crust, of which Dr. Gray considers the fascicle the central axis. The convergent end, in its natural state, is en- veloped in a spongy mass, the fascicle on which Dr. Gray regarded as a parasite. The opinions of scientific men since Gray have been various. Prof. Brandt of St. Petersburg considered the sponge a parasite attaching itself to the polyp mass and gradually destroying it. Dr. Bower- bank regards all the structures above named as parts of one sponge, the wart-like elevations being the oscula. Prof. Schultze of Bonn rep- resents the fascicle and the sponge mass as belonging together, the warty crust being re- ferred to the polyp palythoa. Ehrenberg re- gards the fascicle as an artificial product of Japanese industry, and all sponges as of vege- table nature. In 1867 Prof. Loven described a little, stalked, deep-sea sponge from the coast of Norway, the H. boreale, which led him and naturalists since to the belief that this sponge had been represented upside down; in fact, that the glassy threads were below, mooring the structure to the sand, mud, or weeds, the sponge mass forming the upper portion ; an opinion which Dr. Leidy in 1870 modified by suggesting that this sponge may be suspended by its glassy cable, thinking it highly improba- ble that it should be attached by or rest upon the base where the large oscula are placed. All agree that there is a sponge mass attached