An introduction to dental anatomy and physiology : descriptive and applied.

  • Hopewell-Smith, Arthur, 1865-1931.
Date:
1913
Catalogue details

Licence: Public Domain Mark

Credit: An introduction to dental anatomy and physiology : descriptive and applied. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    The order Monotremata {Mom;—single; Trjyj/JM—aperture) include the Ornithorhynchus (Duck-billed platypus) and Echidna. They may be defined as Mammalia with no teats but with a temporary pouch in which the young are hatched, or to which they are transferred after hatching, and into which open the ducts of the mammary glands. . . . Mammary glands of the sudoriparous and not the sebaceous type of epidermic gland. Oviparous, with a large-yolked and meroblastic ovum, enclosed within a follicle of two rows of cells. ^ Fig. 325 Jaws of a duck-billed platypus {Ornithorhynchus.) X f. The jaws are placed side by side to show their relative proportions. The most salient feature of the group is that the eggs are large- yolked and develop, so far as regards their early stages, therefore, after the fashion of the egg of a reptile. There are some existing Families of these archaic creatures, {i) the Echidnidcz, and {ii) the Ornithorhynchidce.