petromastoid

[English petrous, and mas toid.] Anat.: Of or belonging to the mastoid and to the petrous bone. pět-ro-měs, s. [Pref. petro-, and Gr. mysa mouse.] Zool. Rock-rat; a genus of Octodontine, or, in some cla ifications, of Echimyide. There is but one species, Petromys typic us , from South Africa. pět-ro-my-zon, s . [Pref. petro- , and Gr. myzo = to suck.] Ichthy.: Lamprey; the typical genus of the family Petromyzontide. Dorsal fins two, the posterior continuous with the caudal; lingual teeth serrated. The genus is confined to the northern hemisphere. adj. suff. -idœ.] pět-rō-my-zon-ti-dæ, subst . pl . [Modern Latin petromyzon , gen it. petromyzontid (is); Lat. fem. pl. Ichthy.: Lampreys; a family of Cyclo stomata. Body eel-shaped, naked; subject to a metamorphosis; in the perfect stage, with a suctorial mouth armed with teeth. Eyes present in mature animals. External nasal apertures in middle of upper side of head. Larve without teeth and with a single continuous vertical fin. Genera: Petromy. zon, Ichthyomyzon, Mordacia, and Geotria. Habitat, the rivers and coasts of temperate regions. They feed on other fishes, to which they attach themselves by suction, scraping off the flesh with their teeth. chin, bench; go, gem; thin, this;