The treasury of natural history, or, A popular dictionary of zoology / by Samuel Maunder.

  • Maunder, Samuel, 1785-1849.
Date:
1870
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Licence: Public Domain Mark

Credit: The treasury of natural history, or, A popular dictionary of zoology / by Samuel Maunder. Source: Wellcome Collection.

    801/856 (page 779)
    ill of a Rhynchosaur has been found in t: so-called sandstones near Elgin. PPARTHENOGENESIS. A term proposed r Prof. Owen to iudieate “ procreation with- . t the immediate influence of the male, oiich thus might be understood to embrace .thin its meaning all the phenomena of ►•(similar digenesis or alternate generation, »well as some modes of extension of the ^cies which are not strictly referable to :c.ernate generation. Parthenogenesis in- i. ides reproduction by spontaneous divi- »n or fission, such as we see taking place Actiniadie, by budding or gemmation. . ch as we see in Hydridce and polyps nerally, and by germ-cells, as in the v tual viviparous Aphides. Both in plants d animals true sexually mature indi- Juals have been produced without the . imediate impregnation of the ova or germs im which they have directly originated, or details of Parthenogenesis, see Aetek- ixtiox OF Ge.veuatio.n above.] rPHALLUSIA. A name proposed by Sa- gny to indicate a genus of tunicated mol- scs or Ascidians. It is synonymous with e genus Cynthia, in which the sessile body covered by a leathery tunic furnished ith quadrangular anal and branchial ori- •:es. [See Ascidia, p. 39.] 'PHASCOLOMYS GIGAS. At p. 745 ill be found a description of the Wombat '. xcombcit), which had an ancient repre- ntative of comparatively gigantic propor- jns. This old marsupial, which has been tscribed under the generic and specific title : >ove given, appears to have attaiued the . agnitude of our existing tapir, as is evinced v r the size of its teeth, procured from the eistoceue deposits of the Australian con- sent. : PH ASCOLOTHERIUM. A highly infe- sting genus of marsupial quadrupeds, the •sail remains of which have been found in ie Stonesfield slate. The species was first •scribed by Mr. Broderip from a specimen hich he purchased, when a student at Ox- rd, from an old stonemason, who brought it «sh from the quarry. He named it Didel- lis Bucklandi, in compliment to the able ithor of the Bridgewater Treatise on Mine- l dogy and Geology. Professor Owen has iown how nearly it was related to some of ie living marsupials of Australia, and has idicated the great similarity of, and inte- t rating correspondence between, other exist- ig forms now confined to the Australian con- nent and the circumjacent seas, and the .rganic remains of the British oolite. For istance, the bony “palates, as they have ■ ;en called, which are found in that forma- on, have been evidently the teeth of gigan- c forms of cartilaginous fishes allied to the xisting Cestracion, a Ray-like shark inlia- iting the seas of Australia. TriyonUe, in- treating bivalves confined to the Australian cos, are met with in a fossil state in the ■ ime beds which contain the Phascolothe- um. The plants, too, found in the oolite re closely allied to the Araucaria and dif- ferent Cycadeous plants which grow in Aus- tralia. This curious genus is only known by the jaw, which is preserved in the British Museum. Some naturalists had referred it to the reptile cluss ; but the detailed exami- nation and reasoning of Professor Owen have shown the correctness of its original de- scriber in referring it to the mursupial ani- mals. It is one of the oldest mnmmiferous remains which have yet occurred on the globe. PISTOSAURUS LONGiEVUS. The name applied by Yon Meyer to indicate a species and genus of sauropteryginn reptiles or fin-lizards, whose fossil remains have been discovered in the muschelkalk forma- tion at Buyreuth. PLACODUS. A genus of extinct verte- brates generally classed with the fishes, but recently pointed out by Prof. Owen to be referable to his sauropterygian order of reptiles. The geuuB embraces many species, whose chfef characteristics lay in the pos- session of powerful internal palatine and pterygoidean teeth, in addition to the ordinary well-marked dentition of the jaws. The grinding teeth are massive, resembling paving stones, and “ the size of the last tooth in P. laticeps surpasses that of any of the teeth in the previously discovered species. In proportion to the entire skull, it is the largest grinding tooth in the animal king- dom, the elephant itself not excepted. We cannot contemplate, adds the Professor, ** the extreme and peculiar modification of form of the teeth in the genus Placodus, with- out a recognition of their adaptation to the pounding und crushing of hard substances, and a suspicion that 'he association of the fossils with shell-clad mollusks in such multitudes as to have suggested special denominations to the strata containing Plawxlw (e. g. muschelkalk, terebratuliten- kal, &c.1, is indicative of the class whence the Placodi derived their chief subsistence. As will be readily understood, several in- teresting cranial peculiarities co-ordinated with these astonishing dental modifications. PLAGIAULAX. In the so-called “ dirt- bed formation, Mr. Beccles has discovered a number of extremely interesting fossils, among the most valuable of which are remains of two extinct mammals, severally described by Dr. Falconer under the titles of ' P. Becclesii und P. minor. These vertebrutes | are supposed by Prof. Owen to have been carnivorous marsupials, having some close affinities to a much larger marsupial (Thy hi- coleo), whose fossil remains occur in the newest tertiary deposits of Australia. The generic name has reference to the oblique grooving on the crowns of the grinding teeth. PLEUROSTERNON. The generic name applied by Prof. Owen to several extinct tortoise-like reptiles, whose fossil remains occur in the freshwater limestone of Pur beck. The fossils representing the various species of this genus, associated with other allied Chelonians of the Weulden formation, are