Zygosaurus
in palæontology, a genus of Labyrinthodontia. Skull irregular, with concave sides, an obtuse snout, and a concave occipital border; it is lofty in the occipital region, while falling gradually in front and rapidly on the sides. Orbits slightly posterior, large, irregular. Premaxillary teeth two or more on each side, larger than the maxillary teeth, which are 16 or 18 on each side; all are conical, strong, and nearly straight, with about 20 grooves at the base. Known species one Z. lucius, from the Zechstein (Middle Permian), of the province of Perm in Russia.
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Zygospore
in botany, the term applied by Huxley to the product of conjugation of spores when it is impossible to say which represent the male and which the female element, there being no morphological difference between the modified hyphle which enter into relation with one another.
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Zymotic Diseases
a name applied to epidemic and endemic contagious diseases, because they are supposed to be produced by some morbific principle which acts on the human system like a ferment. This morbific principle or poison gets into the blood in minute particles or germs, and there increases or multiplies, the disease lasting till the poison has become forked out, or has been destroyed. The chief of these diseases are measles, scarlet fever, smallpox, typhus, typhiod, diphtheria, whooping cough, croup and erysipelas.
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