TURKETIN TURTLE 79 and prominent ; the head is so placed on the neck as to allow the nostrils to he easily raised above the surface, their openings heing closed by a fleshy valve. Much sea water is swal- lowed with their food, and when the former is of necessity regurgitated the latter is re- tained by the numerous horny processes, point- ing backward, in the oesophagus. The very young are longer in proportion to their width, and grow broader. Though lower than the tortoises, the turtles exhibit features resem- bling those of birds in the form of the anterior limbs, the mode of locomotion, the preponder- ance of the fore part of the body, bill-like jaws, and overlapping epidermic appendages. All are marine, excellent swimmers, and rarely ap- proach the shore except to deposit their eggs ; some feed entirely on sea weeds, but a few eat mollusks, crustaceans, and other aquatic ani- mals ; they are generally timid, and make but little resistance, though they are more bold and regardless of danger in the pairing season. The flesli of- the herbivorous species is a whole- some food, and much sought after by epicures, while that of the carnivorous is disagreeable if not positively injurious ; the callipee, or under part of the breast and abdomen, is con- sidered the choicest part ; the liver and fat are also much esteemed. They come on shore to- ward the end of spring to lay their eggs on the sandy beaches above high-water mark ; they generally select desert islands or keys, and a still moonlight night ; they dig a trench in the sand with their hind feet about 1 ft. deep, and deposit therein about 100 eggs at each of three layings, with an interval of two or three weeks between them ; the eggs are lightly cov- ered with sand, and left to be hatched by the heat of the sun ; if undisturbed, they return to the same shore year after year. They are caught on the shore, and turned on their backs, a position from which they cannot es- cape, owing to the flatness and width of the shell ; they are harpooned and taken in nets in the water, and in the Indian seas are cap- tured by means of the remora. (See SUCKING FISH.) In the chelonioidm the body is widest about midway, and the vertebral column de- scends continuously and gently to the tail ; the shoulders and hind limbs are better protected than in the other family ; the shield is more or less heart-shaped, with the posterior angle not prolonged into a point extending far over the tail ; all the genera are represented on the coast of the United States, and are far less rapid swimmers than the sphargididce. The latter family has only the single genus sphargis (Merrem), showing well the inequality of the natural groups called families ; the body is more conical than in the other turtles, the carapace leaving the hind legs as well as the shoulders and neck much exposed from its great contraction behind and in front ; the low- er parts are equally unprotected by the plas- tron, this with the carapace forming little more than a wide girdle around the thorax and ab-
Page:The American Cyclopædia (1879) Volume XVI.djvu/91
This page needs to be proofread.