- Representative Mammalian, Avian and Reptilian Trypanosomes, to illustrate the chief morphological characters.
There is a well-marked processus lateralis anterior (the right and left together equivalent to the mammalian manubrium), which is the product of two or three ribs, the dorsal parts of which reduced ribs remain as cervico-dorsal ribs.
The muscles of the limbs show a great amount of specialization, away from the fundamental reptilian and mammalian conditions.
This great muscle covers completely the supracoracoideus, generally described as the second pectoral, or subclavius muscle, in reality homologous with the mammalian supraspinatus muscle.
Auditory ment in the crocodile, and with the ", chain " of Chicken, X 6 processus folii of the mammalian diameters; lateral and basal malleus, it follows that the whole views.
It receives the three great venous trunks of the body, namely the vena cava superior dextra, the vena cava superior sinistra more dorsally, and the vena cava inferior more to the right and below; the opening of the last is guarded by two prominent valves in place of the mammalian valvula Eustachii.
The communication with the atrium is guarded by a valvula cardiaca dextra, which only in function represents the mammalian tricuspid; it consists of an oblique reduplication of the muscular fibres together with the endocardiac lining of the right ventricle, while the opposite wall is convex and forms neither a velum nor papillary muscles, nor chordae tendineae.
The walls of these tertiary tubes send out, in all directions, canaliculi aeriferi which, ending in slight swellings, recall the mammalian aveoli.
Owing to the comparatively scanty number of harmful mammalian types, the birds play a considerable part in this large region, and some authorities consider its avifauna the richest in the world.
In it various fossil mammalian remains have been found.
CHEVROTAIN, a name taken from the French to designate the various representatives of the mammalian ungulate family Tragulidae.
The mammalian remains found in Pleistocene deposits are of exceptional interest.
BEAVER,' the largest European aquatic representative of the mammalian order Rodentia, easily recognized by its large trowel-like, scaly tail, which is expanded in the horizontal direction.
Following Cuvier's Recherches sur les ossemens fossiles, the rich succession of Tertiary mammalian life was gradually revealed to France through the explorations and descriptions of such authors as Croizet, Jobert, de Christol, Eymar, Pomel and Lartet, during a period of rather dry, systematic work, which included, however, the broader generalizations of Henri Marie Ducrotay de Blainville (1778-1850), and culminated in the comprehensive treatises on Tertiary palaeontology of Paul Gervais (1816-1879).
We are thus working out gradually the separate contributions of the land masses of North America, South America, Europe, Asia, Africa, and of Australia to the mammalian fauna of the world, a result which can be obtained through palaeontology only.
Xlii., 1893), " Ten Years' Progress in the Mammalian Palaeontology of North America " (Comptes rendus du 6 e Congres intern.
Brucei),' among mammalian forms, described by Prowazek (47); T.
As in other parts of the world, the chiefest palaeontological interest of the Tertiary attaches to the mammalian fossils.
4) represents an ideal mammalian liver.
The Alluvium was distinguished from Diluvium by the fact that its mammalian fossils were representatives of still living forms, but it is a matter of great difficulty to separate these two divisions in practice.
The fluvio-marine deposits of the Upper Eocene and Oligocene formations contain an interesting mammalian fauna, proving that the African continent formed a centre of radiation for the mammalia in early Tertiary times.
Although the British representatives of this group should undoubtedly retain their vernacular designations of water-rat and short-tailed field-mouse, the term "vole" is one of great convenience in zoology as a general one for all the members of the group. Systematically voles are classed in the mammalian order Rodentia, in which they constitute the typical section of the subfamily Microtinae in the Muridae, or mouse-group. As a group, voles are characterized by being more heavily built than rats and mice, and by their less brisk movements.
Especial importance attaches to the unexpected discovery by Whitehead of a new and peculiar mammalian fauna, inhabiting a small plateau on the top of Mt Data, in north Luzon, at an altitude of more than 7000 ft.
The caves of the Kyrenian range contain a Pleistocene mammalian fauna.
HYENA, a name applicable to all the representatives of the mammalian family Hyaenidae, a group of Carnivora allied to the civets.
Many interesting mammalian fossils, rhinoceros, mammoth, &c., with palaeolithic implements, have been found in the valley gravels of the river Ouse and its tributaries.
An osteological question which has been much discussed is the fate of the reptilian quadrate bone in the mammalian skull.
Although the present article does not discuss mammalian osteology in general (for which see Vertebrata), it is interesting to notice in this connexion that the primitive condition of the mammalian tympanum apparently consisted merely of a small and incomplete bony ring, with, at most, an imperfect ventral wall to the tympanic cavity, and that a close approximation to this original condition still persists in the monotremes, especially Ornithorhynchus.
The tympano-hyal is the characteristic mammalian element in this region; but the entotympanic likewise appears to be peculiar to the class, and to be unrepresented among the lower vertebrates.
Two other points in connexion with mammalian osteology may be noticed.
The third upper molar (m 3) is the only tooth wanting to complete the typical heterodont mammalian dentition.
In this generalized form of mammalian dentition the total number of teeth present is 44, or II above and II below on each side.
From this point of view the various adaptive modifications of mammalian dentition may be roughly grouped under the headings of piscivorous, carnivorous, insectivorous, omnivorous and herbivorous.
In some mammals, notably lemurs, occurs a hard structure known as the sublingua, which may terminate in a free horny tip. If, as has been suggested, this organ represents the tongue of reptiles, the mammalian tongue will obviously be a superadded organ distinctive of the class.
Possibly mammalian remains also occur in the antecedent Triassic epoch, some palaeontologists regarding the South African Tritylodon as a mammal, while others consider that it was probably a reptile.
Osborn, the tripartite reptilian condyle, by the loss of its median element, has given rise to the paired mammalian condyles; so that this difficulty disappears.
That is to say, he believes that, with the exception of the duckbill and the echidna, the mammalian class as a whole can lay claim to descent from small arboreal forms. This view is, of course, almost entirely based upon palaeontological considerations; and these, in the author's opinion, admit of the conclusion that all modern placental and marsupial mammals are descended from a common ancestral stock, of which the members were small in bodily size.
On the other hand, towards the close of the Cretaceous epoch (when the Chalk was in course of deposition), the spread of a great upland flora vastly extended the territory available for mammalian life.
This absence of mammalian life in oceanic islands extends even to New Zealand, where the indigenous mammals comprise only two peculiar species of bats, the so-called Maori rat having been introduced by man.
One of the leading features in mammalian distribution is the fact that the Monotremata, or egg-laying mammals, are exclusively confined to Australia and Papua, with the adjacent islands.
Very different, on the other hand, is the condition of things in Australia and Papua, where marsupials (and monotremes) are the dominant forms of mammalian life, the placentals being represented (apart from bats, which are mainly of an Asiatic type) only by a number of more or less aberrant rodents belonging to the mouse-tribe, and in Australia by the dingo, or native dog, and in New Guinea by a wild pig.
Parker, Mammalian Descent (London, 1885); E.
COATI, or COATI-MUNDI, the native name of the members of the genus Nasua, of the mammalian family Procyonidae.
The avi-fauna is much richer than the mammalian, and, although wanting the 'largest birds as well as the most brilliantly coloured, comprises two hundred and sixty species, half of which are endemic. Many of the birds are remarkable not so much for their shape or colouring as for their distant relationships; many belong to peculiar genera, and some are so isolated that new families have had to be formed for their reception.
The great number and variety of mammalian remains has made it possible for the Tertiary rocks to be classified by their means: see A.
The muscles of the limbs are modified from those of the ordinary mammalian type in accordance with the reduced condition of the bones and the simple requirements of flexion and extension of the joints, no such actions as pronation and supination, or opposition of digits, being possible or needed.