Trituberculy

Trituberculy
Trituberculy Tri`tu*ber"cu*ly, n. [Pref. tri- + L. tuberculum tubercle.] (Zo["o]l.) A theory of the development of mammalian molar teeth. The primitive stage is that of simple cones, as in reptiles. The simple cone then developed a smaller cone in front and another behind. Next, a cingulum was developed, and the three cones became arranged in a triangle, the two smaller cusps having moved to the outer side in upper and to the inner in lower molars. This primitive triangle is called the trigon or trigonid and this stage the tritubercular or trigonodont. The trigon being a cutting apparatus, an extension of the posterior part of the crown was developed in lower molars for crushing, and a smaller corresponding part appeared in upper molars. Another large cone then arose, usually from the cingulum. In more complex forms, smaller intermediate cusps appeared. [Webster 1913 Suppl.]

The Collaborative International Dictionary of English. 2000.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • trituberculy — tri·tu·ber·cu·ly …   English syllables

  • trituberculy — lē noun ( es) Etymology: trituberculate + y : the state of being tritubercular or showing evidence of having developed from a tritubercular ancestral type used especially in reference to a theory of the origin of mammalian molar teeth supposing… …   Useful english dictionary

  • Trigonodont — Trig o*no*dont , a. [See {Trigon}; {Odonto}.] See {Trituberculy}. [Webster 1913 Suppl.] …   The Collaborative International Dictionary of English

  • Tritubercular — Tri tu*ber cu*lar, a. (a) Having or designating teeth with three cusps or tubercles; tricuspid. (b) Pertaining to trituberculy. [Webster 1913 Suppl.] …   The Collaborative International Dictionary of English

  • William King Gregory — (* 19. Mai 1876 in Greenwich Village; † 29. Dezember 1970 in Woodstock) war ein US amerikanischer Zoologe und Wirbeltier Paläontologe. Gregory studierte zunächst ab 1895 an der Bergbauakademie (School of Mines) der Columbia University, wechselte… …   Deutsch Wikipedia

  • multituberculy — lē noun ( es) Etymology: multituberculate + y : the state of having many tubercles used especially in ref. to a theory of the origin of mammalian teeth; compare trituberculy …   Useful english dictionary

  • trituberculism — ˌtrītəˈbərkyəˌlizəm noun ( s) Etymology: trituberculate + ism : trituberculy * * * trituberˈculism, trituberˈculy noun • • • Main Entry: ↑tritubercular …   Useful english dictionary

  • triconodont — I. trīˈkänəˌdänt adjective Etymology: New Latin Triconodont , Triconodon 1. : having or being teeth with three simple cones compare trituberculy 2. [New Latin Triconodonta] : of or relating to the Triconodonta II …   Useful english dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”