Chelonia

“ No order of reptiles is so unequivocally distinguished from all others as the Chelonia, the turtles and tortoises. Jaws are always [beaked] , and except in Stegochelys of the Trias they are wholly toothless; a short, broad body, a rather short skull, a flexible neck of eight vertebrae, and an osseous carapace and plastron. ”

“ The relations of the bones to the foramen magnum vary considerably, in Chelonia the basi-occipital generally takes no part in bounding it, and in the Theromorpha, Crocodilia, and Ophidia, the supra-occipital is excluded. The parietals are paired in Geckos and Chelonia alone among living forms, and in the extinct Ichthyosauria and some Theromorpha; in all other reptiles they are united. ”

“ A free centrale is absent in all modern reptiles, though sometimes suturally fused with the astragalus in the Chelonia (Fig. 154 c) .
In the Chelonia the small calcaneum is sometimes free (Fig. 154 c) . The centrale is never free. Four tarsalia are usually present, the third sometimes suturally united with the fourth. The fourth tarsale is always large. ”

“ Cope, Dollo, and Boulenger look upon Sphargis as the sole remnant of a primitive group in opposition to all the other recent Chelonia, Baur considered it the most specialised descendant of the Chelonidae. Dames agreed with him. Van Bemmelen has modified this view in so far as he regards Sphargis as the most specialised Chelonian, but considers the differences between it and the Chelonidae great enough to conclude that both Sphargidae and Chelonidae represent two independent, partly parallel, branches which have arisen from two different groups of terrestrial tortoises. ”

“ The skull of the Testudinata or Chelonia is never elongate, though relatively slender in some of the more predaceous kinds. It always lacks the septomaxillae, postfrontals, supratemporals, dermosupraoccipitals, tabulars, ectopterygoids, ethmoids, and the parietal foramen. The nasals are usually absent, and the lacrimals are present only in some ancient forms. The prefrontals are large, meeting in the middle line. The prevomers are single and sometimes obsolete; they usually articulate above with the prefrontals. The parasphenoid has been lately recognized as a distinct bone in certain forms. ”

“ The Chelonia are reptiles of the tortoise kind, and among these Professor Martin selects the Red-bellied Slider Terrapin for dissection, and adapts his book to the details of its structure. But, if students can not find this species, Professor Martin says that it is quite as well, and even in some respects better, to obtain species slightly different from the one described; the attention of students being kept more alert when they find they can not altogether rely on the description in the book, but have to look at everything carefully for themselves. ”

“ The four families into which the Chelonia are classed have all of them a wide distribution, though none are universal. The Ethiopian region seems to be the richest, as it possesses 3 of the four families, while no other region has more than 2; and it also possesses 7 peculiar genera. Next comes the Neotropical region with 2 families and 6 peculiar genera; the Australian with 3, and the Nearctic with 2 peculiar genera; while the Oriental and Palæarctic regions possess none that are peculiar. There are about 30 genera and 200 species in the whole order. ”

“ Among the Chelonian remains of the Wealden, some of the most remarkable are the costal plates and other bones of a Tortoise, which in its essential characters is closely allied to the Trionyces, [689] but differs from the recent forms, in having possessed a dermal horny integument, formed of scutes of tortoise-shell. The chelonians of the genus Trionyx (so named from their having three claws) have the extremities of the ribs free, and not articulated to a border of marginal plates, and there are intervals between their costal plates even in the adult state. ”

“ In the Theromorpha, so far as known, the paroccipitals are fused with the supraoccipital, suturally or loosely articulated with the exoccipitals. In the Chelonia (Fig. 31 b, op) , only of modern reptiles, are they separate bones in the adult, intercalated between the exoccipitals, supraoccipital, proötics, squamosal, and supporting the head of the quadrate. Among other reptiles they are known to be free only in the Ichthyosauria (Fig. 51) , articulating with the basioccipital, exoccipitals, stapes, and so-called supratemporal. ”

“ The Chelonia (tortoises) are represented by the families Testudinidæ and Chelydidæ, both of wide range; but there are six peculiar genera,—Dermatemys and Staurotypus belonging to the former family,—Peltocephalus, Podocnemis, Hydromedusa, and Chelys, to the latter. Some of the Amazon river-turtles of the genus Podocnemys rival in size the largest species of true marine turtles (Cheloniidæ) , and are equally good for food.
Amphibia.—The Neotropical region possesses representatives of sixteen families of Amphibia of which four are peculiar; all belonging to Anoura or tail-less Batrachians. ”

“ The marine Chelonians generally feed upon vegetables; the Emys and Trionyx approach more nearly to the terrestrial than to the marine species; they are carnivorous, feeding on frogs, fishes, fresh-water mollusca, and other small animals. The Trionyces differ from their congeners in being destitute of a horny external integument, having no scutes on the « 728 » buckler or any other part of the body but the osseous carapace is invested with a strong tough skin, which equally covers the dorsum and sternum, to which it firmly adheres ”

“ Bison sp. indet. (p. 261) . Cervus? sp. indet. (p. 243) . Tapirus haysii (p. 206) . Equus complicatus (p. 193) . E. leidyi (p. 193) . E. littoralis (p. 193) . Megatherium mirabile (p. 36) . Mylodon harlani (p. 36) . Chelonia (??) couperi. Crocodylus (?) sp. indet. Lamna sp. indet. Galeocerdo sp. indet. Carcharodon sp. indet. Dasyatis sp. indet. With the bones found in the canal was a femur 13 inches long, which Harlan described as Chelonia couperi, but which resembles more closely that of some edentate mammal. Gidley stated that the shark-teeth probably represent Eocene and Miocene species. ”

“ It is these chelonians whom they “turn”—that is to say, put on their backs—when they come from laying their eggs, and whom they preserve alive, keeping them in palisaded pools like fish-pools, or attaching them to a stake by a cord just long enough to allow them to go and come on the land or under the water. In this way they always have the meat of these animals fresh. ”

“ They appear for the first time, not as modified spinous processes, broadened, as in the carapace of the Chelonians, into osseous plates, but like those corneous external plates of this order of reptiles, (known in one species as the tortoise-shell of commerce,) the origin of which is purely cuticular, and which evince so little correspondence in their divisions with the sutures of the bones on which they rest, that they have been instanced, in their relation to the joinings beneath, as admirable illustrations of the cross-banding of the mechanician. ”

“ Pleurosternum, of the English and Continental Purbeck beds, has meso-plastral plates like the recent Pelomedusidae. Rhinochelys, of the Cambridge Greensand, has a broad parieto-postfrontal roof, and large nasal bones. Forms like Podocnemis, now restricted to South America, occur in the Eocene of Europe. One of the most aberrant Chelonians is Miolania, from the Plistocene of Queensland and from Lord Howe's Island, remarkable for its huge size and the thick armour on the head and tail ”

“ Chelonians show a great divergence in their mode of life,—some living constantly on land, others having partly terrestrial partly aquatic habits, others again rarely leaving the water or the sea. The first-mentioned, the land tortoises proper, have short club-shaped feet with blunt claws, and a very convex, heavy, completely ossified shell. In the freshwater forms the joints of the limb bones are much more mobile, the digits distinct, armed with sharp claws, and united by a membrane or web ”

“ Under this impression he bestowed upon the yet unknown ichthyolite of which they had formed part, the name Chelonichthys, from the resemblance borne by the broken plates to those of the carapace and plastron of some of the Chelonians. At this stage, however, the Russian Old Red yielded a set of greatly finer remains than it had previously furnished; and of these casts were transmitted by Professor Asmus, of the University of Dorpat, to the British and London Geological Museums, and to Agassiz. ”

“ The Chelonians, up to this point only known by the doubtful evidence of footprints in the Permian and Triassic sandstones, are here represented by unquestionable remains, indicating the existence of marine Turtles (the Chelone planiceps of the Portland Stone) . No remains of Serpents (Ophidians) have as yet been detected in the Jurassic; but strata of this age have yielded the remains of numerous Crocodilians, which probably inhabited the sea. ”

“ Inhabits.
85. Chelodina longicollis, Gray Syn. Rep. 39. C. novae hollandae, Dumeril and Bibron Erp. Gen. 2 445 t. 21 f. 2.
Testudo longicollis, Shaw Gen. Zool. 3 62 t. 16. Zool. New Hol. 1 19 t. 7.
Emys longicollis, Schw. Prod. 1 309, 433.
Hydraspis longicollis. Bell Zool. Journal 3 512.
Inhabits New Holland, Sydney.
86. Chelodina oblonga, t. 7 new species.
Inhabits Western Australia.
Family CHELONIADAE.
87. Chelonia caretta.
Testudo caretta, Solander manuscript Banks Icon. ined. in British Museum n. 41, 42, 43.
Inhabits Sea. Latitude 37 South, December 23 1768. Captain Cook. ”

“ The early Chelonians possessed most likely more than five longitudinal dorsal rows of plates. The presence of several small supra marginal shields in M acroclemmys may be an indication that the total number of longitudinal rows was originally at least seven. The number of transverse rows, both of plates and shields, was also greater. /Ve can account for at least twelve median plates and as many pairs of marginals, but for only eight median and eight pairs of costal shields (individual variations observed in Thalassochelys) . ”

“ Through the space enclosed by the pterygoid, basioccipital, opisthotic and quadrate, enters the cranial carotid artery, sometimes piercing the posterior rim of the pterygoid; then the canal runs along the dorsal side of this bone and opens near the cranial columella. The arcades over the temporal region are most variable. Potentially Chelonians possess all the three arcades of the crocodiles, but it so happens that never more than one fenestra is present. The false roof over the temporal region is most complete in Sphargis and in the Chelonidae. ”

“ Chelonis, far from sharing in her husband's good fortune, retired into the same temple with her father, and dwelt there with him in mortification and penance. Afterwards he was permitted to retire to Tagea, whither Chelonis also accompanied him. Cleombrotus, in his turn, being dethroned, Leonidas was restored to his kingdom; but Chelonis, no longer sensible of her husband's fault, determined to share his misfortune with him, though she had no share in his prosperity. ”

“ The generous Chelonis gave a signal instance, upon this occasion, of that heroick virtue, for which the Spartan ladies were once so remarkably eminent. When her father was expelled by the intrigues of Lysander, she followed him into exile, and refused to share his crown with Cleombrotus. In this calamitous reverse of fortune, she was deaf to all entreaties, and rather chose to partake of the miseries of banishment with her husband, than all the pleasures and grandeur of Sparta with her father. ”

“ The long-beaked Chelmon's body is yellow. Instead of the stripe crossing the eye, seen in the other species, we find on the anterior portion of the body a broad, blackish spot, triangular in shape, and terminating in a point on the snout. This spot is bordered by a nacreous white stripe; the forehead is of azure tint, with a shade of sea-green; the eye is of a pure rose-color; a narrow stripe of black adorns the margin of the fins, which themselves are of mauve-color ”

“ In the beaked Chelmon the body is greenish and iridescent; the fins are green, with reflection of azure; a black spot, surrounded by a pearl-white circle, is seen on the dorsal fin, in length about one-third that of the soft rays; five vertical stripes of azure-color, and bordered with a nacreous white line, adorn the body; one of these stripes crosses the eye obliquely; a second one, bisecting the nape of the neck, extends to the ventral fins; the next two mark the flanks, and the posterior stripe bisects the root of the caudal fin. ”

“ Chelonis, then, pointing to her mourning habit and her dishevelled hair thus addressed Leonidas. ‘It was not my dear father compassion for Cleombrotos which put me in this habit and gave me this look of misery. My sorrows took their date with your misfortune and your banishment, and have ever since remained my familiar companions. Now you have conquered your enemies and are again king of Sparta should I still retain these ensigns of affliction or assume festival and royal ornaments, while the husband of my youth whom you yourself bestowed upon me falls a victim to your vengeance? ”

“ But Chelonis did not hesitate. As Cleombrotus rose to go, she gave him one of her children, and, taking the other in her arms and kissing the altar of the goddess, she walked out with him to degradation and poverty.
Justly does Plutarch add the remark that if Cleombrotus had not been entirely corrupted by vainglory, he would have deemed exile with such a woman a greater blessing than any kingdom. The fate of pure-minded Agis was worse than that of Cleombrotus. No mercy was shown him, and he was put to death by strangulation. His mother, Agesistrata, waited to hear what was to become of him. ”