. Evolution and disease . e inguinal set functional as inthe cow, mare, sheep, goat, deer, and antelope. Theinguinal glands may abort, leaving the pectoral setfunctional as in man, dugong, sloth, manatee, andmonkeys. In marsupials the milk-glands are inguinalin position, and protected by the remarkable fold ofskin which forms the pouch or marsupium. The lemurs offer instructive modifications. The ring-tailed lemur {L. catta), the black lemur {L. macaco), andthe mongoose lemur (Z. niongoz), possess one pair ofpectoral mamma;, as in man and quadrumana, Co-querels mouse lemur {CJiirogaleiis coqii
. Evolution and disease . e inguinal set functional as inthe cow, mare, sheep, goat, deer, and antelope. Theinguinal glands may abort, leaving the pectoral setfunctional as in man, dugong, sloth, manatee, andmonkeys. In marsupials the milk-glands are inguinalin position, and protected by the remarkable fold ofskin which forms the pouch or marsupium. The lemurs offer instructive modifications. The ring-tailed lemur {L. catta), the black lemur {L. macaco), andthe mongoose lemur (Z. niongoz), possess one pair ofpectoral mamma;, as in man and quadrumana, Co-querels mouse lemur {CJiirogaleiis coqiiereli), and thedwarf lemur {Microcebus sviit/ii), possess three pair ofmammary glands : one pair in the pectoral, another in 164 EVOLUTION AND DISEASE. the thoracic, and the third pair in the inguinal region(fig. 86). It is said, but I have had no opportunity ofverifying the statement, that Tarsius spectrum has aninguinal and a pectoral pair of milk-glands ; the aye-aye {Chcironiys) has only an inguinal pair ; lastly, the. Fig. 86.—a Dwarf Lemur {Microcchus siiiillii), showing thearrangement of the mammary glands. gray, or broad-nosed lemur {^Hapaleiuur griseus), has themammary glands situated on its arms.^ The above facts (with the exception of those relatingto Hapaleninr) seem to indicate that the lemurs havedescended from ancestors possessing two rows ofmamma;. In the dwarf lemurs, the abdominal pair ■ Beddard, Proc. Zool. Soc. ATAVISM. 165 have disappeared, whilst in the ring-tailed, black, andmongoose lemurs the pectoral pair alone persist. The persistence of the pectoral pair in these lemursmay possibly be explained by the curious manner inwhich they carry the young. Lemur macaco has usuallyone at a birth, and this is carried about entwined aroundits mother in the manner represented in fig. 88. I havewatched the young lemur, and find that it rarely leavesits mother, and it is clear that whilst holding on in this
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectabnormalitieshuman
