L 8

l 8, s 6, ca 25. the large number of lumbar vertebrae is peculiar among edentates. the tongue is less worm-like than in _myrmecophaga_, being thick and fleshy at the base and gradually tapering to the apex. the salivary apparatus is developed much in the same manner as in that genus, but the duct of the submaxillary gland has no reservoir. the stomach consists of a large subglobular cardaic portion, with a thick, soft, and corrugated lining membrane, and a smaller muscular, pyloric part, with a comparatively thin and smooth lining. there is a distinct ileocaecal valve and a considerable sized caecum; also a gall-bladder. head elongated, with a tubular snout, terminal nostrils and small mouth-opening. ears large, pointed, erect. tall nearly as long as the body, cylindrical, thick at the base, tapering to the extremity. according to the researches of dr e. lonnberg, the teeth of the aard-varks correspond only to the roots of those of other mammals, the crowns being unrepresented, except to a very small degree when the teeth first cut the gum. this explanation renders the peculiar internal structure of these teeth much less difficult to understand than if they represented both crown and root. in dr lonnberg's opinion, the teeth indicate the descent of the aard-vark from an ungulate stock,--a view in harmony with the evidence of the brain. if this idea prove well founded, and if the aard-varks are rightly classed with the edentata, the whole order must apparently be regarded as an offshoot from primitive ungulata. the fact of the frequent distinctness of the coracoid bone requires, however, explanation in connexion with such a descent (see aard-vark). _pholidota._--the pholidota, constituting the third and last group of the edentata, are represented by the pangolins, or scaly anteaters, of asia and africa, all of which are included in the family _manidae_ and the genus _manis_. pangolins differ from all other mammals by the armour of overlapping horny scales (often with hairs growing between them) which invests the whole animal, with the exception of the under surface of the body, and sometimes a small patch near the tip of the under side of the tail. there are no teeth; and although the tongue is long and worm-like, it is not extensile. the scaphoid and lunar bones of the carpus are united. the uterus is bicornuate, and the placenta diffused and non-deciduate. the skull has somewhat the form of an elongated cone, with the small end turned forwards, and is smooth and free from crests and ridges. no distinction between the orbits and temporal fossae. the zygomatic arch usually incomplete, owing to the absence of the jugal bone; no distinct lacrymal bone; and the palate long and narrow. the pterygoids extend backwards as far as the tympanics, but do not meet in the middle line below. tympanic welded to the surrounding bones, and more or less bladder-like, but not produced into a tubular auditory meatus. two halves of lower jaw very slender and straight, without any angle or coronoid process, on the anterior extremity of the upper edge a sharp, conical, tooth-like process projecting upwards and outwards. no clavicles. no third trochanter to the femur. terminal phalanges cleft at the tip. caudal vertebrae with very long transverse processes and numerous chevron-bones. stomach with thick muscular walls and lining membrane, and a special gland near the middle of the great curvature, consisting of a mass of complex secreting follicles, the ducts of which terminate in a common orifice. no caecum, but a gall-bladder. head small, depressed, narrow, and pointed in front, with a very small mouth-opening. eyes and ears very small. body elongated, narrow. tail more or less elongated, convex above, flat underneath. limbs short, and in walking the surface and outer sides of the phalanges of the two outer digits of the front feet alone rest on the ground, with the points of the nails turning upwards and inwards. the third toe the longest, with a powerful compressed curved claw, the second and fourth with similar but smaller claws, but that of the first toe often almost rudimentary. hind-feet plantigrade with the first toe very short, and the four other toes subequal, and carrying moderate, curved, compressed nails. pangolins are of small or moderate size, terrestrial and burrowing, and feed mainly on termites or white ants; some of the species being more or less arboreal. they can roll themselves up in a ball when in danger. their peculiar elongated form, short limbs, long tapering tail, and scaly covering give them on a superficial inspection more the appearance of reptiles than of mammals. the species are not numerous and may be divided into two sections, one comprising the asiatic species, such as _m. javanica_, _m. aurita_ of china, and the indian _m. pentadactyla_, and the other the african, as represented by the large _m. gigantea_, _m. temminchi_, the long-tailed _m. macrura_, and the small arboreal _m. tricuspis_. in the asiatic group the middle series of scales continues to the tip of the tail; but in the african forms this row splits into two a few inches from the tail-tip. the latter have also no hairs between the scales and no external ears. the climbing species have a small bare patch on the under side of the tail near the tip (see pangolin). _extinct edentates._ beyond remains of species closely allied to or identical with the existing forms, the sloths and anteaters appear to be unknown in a fossil state. on the other hand the extinct family of ground sloths, or _megatheriidae_, which includes the largest of all edentates, is an exceedingly large one, and extends in south america from the miocene to the pleistocene, and was also represented during the latter epoch in north america. it serves to connect the _bradypodidae_ with _myrmecophagidae_. the alleged occurrence of an allied form in madagascar is somewhat doubtful (see megatherium and mylodon). of _dasypodidae_ numerous representatives occur in the south american tertiaries. from the higher beds many of the species are referable to existing genera, such as _dasypus_ and _tatusia_, although some are much larger than any living forms, the skull in one case being nearly a foot in length. in other instances, when lower formations are reached, the genera are also distinct, _eutatus_ having the whole armour divided into movable bands, and the allied _stegotherium_ representing the group in the santa cruz formation of patagonia. even in the argentine pleistocene there is an extinct genus, _chlamydotherium_, represented by a species of the size of a rhinoceros, with grooved teeth approximating to those of the glyptodonts. the latter represent a family (_glyptodontidae_) by themselves, and typically may be described as giant solid-shelled armadillos, although some of their smaller santa cruz representatives (_propalaeohoplophorus_) approximate in some degree to true armadillos (see glyptodon). a very remarkable santa cruz armadillo, _peltephilus_, has an altogether peculiar type of head-shield, developed into horns in front of the eyes; and, what is still more noteworthy, teeth in the front of the jaws, thereby rendering the ordinary definition of the order edentata incorrect. it has been made the type of a distinct family, _peltephilidae_. the past history of the armadillo group does not, however, by any means end here. true armadillos, it should be observed, are known in north america as far north as texas, from the pleistocene onwards; but in formations of middle tertiary age are unrepresented. recent discoveries apparently indicate, however, the occurrence of armadillos of a primitive type in the lower tertiary or eocene formations of wyoming. the first evidence of these eocene armadillos was afforded by portions of the jaws, which, together with a leg-bone of a totally different animal, were believed to indicate creatures nearly allied to the aye-aye (_chiromys_) of madagascar, and for which the name _metachiromys_ was consequently proposed. according to modern usage, this name, in spite of its inappropriate nature, is retained for the armadillos, although in the writer's opinion it ought to be replaced. according to professor h.f. osborn, by whom their remains have been described, the north american fossil armadillos were closely related to the existing members of the group, from which they differ chiefly by the armour, or shield, having probably been formed of tough leathery skin instead of bony plates, by the presence of a single pair of large enamel-capped tusk-like teeth in each jaw, and by the degeneration of the other teeth. if these determinations are trustworthy, the question arises whether we should regard the armadillos of south america as the descendants of north american forms which migrated southwards before that separation of the two continents was established, which lasted for a large portion of the tertiary period, or whether a migration took place at the same early epoch in the opposite direction. more interesting still is the occurrence of remains of reputed armadillos (_necrodasypus_) from the oligocene of france and germany. in the opinion of dr f. ameghino these oligocene armadillos, which had bony shields on both the head and body, were near akin to some of the modern south american forms. passing on to the aard-varks (_orycteropodidae_), we find these represented by a species closely allied to the existing ones in the lower pliocene formations of spain, france, hungary, samos and asia minor. a single tibia from the french oligocene is identified by dr ameghino with the present family, and the genus _archaeorycteropus_ established for its reception; this genus, in its founder's opinion, being also represented in the santa cruz beds of patagonia. as regards the pangolins, the only fossils referred to this group (apart from a few discovered in a cave in india) appear to be certain limb-bones from the oligocene of france and germany, for which the names _necromanis_ and _teutomanis_ have been proposed. the occurrence of the characteristic cleft terminal toe-bones among these remains seems to leave little doubt as to the correctness of the determination. the alleged occurrence of remains of giant pangolins in the upper tertiary of europe is due to misidentification (see ancylopoda). by some authorities the eocene group of ganodonta has been affiliated to the edentata, but this reference is not accepted by prof. w.b. scott. authorities.--the above article is to some extent based on the articles by sir w.h. flower in the 9th edition of this work. see also o. thomas, "a milk-dentition in _orycteropus_," _proc. royal soc._ vol. xlvii. (1890); r. lydekker, "the extinct edentates of argentina," _palaeont. argentina_, vol. iii., an. mus. (la plata, 1894); c.w. andrews, "on a skull of _orycteropus gaudryi_ from samos," _proc. zool. soc. london_ (1896); g.e. smith, "the brain in the edentata," _trans. linn. soc. london_, vol. vii. (1899); w.b. scott, "mammalia of the santa cruz beds--_dasypoda_," _rep. princeton exped. to patagonia_, vol. v. (1903); h.f. osborn, "an armadillo from the middle eocene of north america," _bull. amer. mus._ vol. xx. art. 12 (1904); j.a. allen, "the tamandua anteaters," _t.c._, art. 33 (1904); f. ameghino, "les edentes fossiles de france et d'allemagne," _ann. mus. buenos aires_, vol. xiii. (1905); e. lonnberg, "on a new _orycteropus_," and "remarks on the dentition of the tubulidentata," _archiv fur zoologie_, vol. iii. no. 3 (1906). (r. l.*)