834 OLOSSABY 



Tarsus (pi. Tarsi).— The jointed feet of articulate animals, 

 such us Insects. 



Teleostean Fishes. — Fishes of the kind familiar to us in 

 the present day, having the skeleton usually completely 

 ossified and the scales horny. 



Tentacula or Tentacles. — Delicate fleshy organs of 

 prehension or touch possessed by many of the lower 

 animals. 



Tertiary. — The latest geological epoch, immediately pre- 

 ceding the establishment of the present order of things. 



Trachea. — The windpipe or passage for the admission of 

 air to the lungs. 



Tridactyle. — Three-fingered, or composed of three movable 

 parts attached to a common base. 



Tbilobites. — A peculiar group of extinct Crustaceans, 

 somewhat resembling the Woodlice in external form, 

 and, like some of them, capable of rolling themselves 

 up into a ball. Their remains are found only in the 

 Paleozoic rocks, and most abundantly in those of 

 Silurian age. 



Trimorphic. — Presenting three distinct forms. 



UmbellifeRuE, — An order of plants in which the flowers, 

 which contain five stamens and a pistil with two styles, 

 are supported upon footstalks which spring from the top 

 of the flower stem and spread out like the wires of an 

 umbrella, so as to bring all the flowers in the same head 

 {umbel) nearly to the same level. {Examples^ Parsley 

 and Carrot.) 



Ungulata. — Hoofed quadrupeds. 



Unicellular. — Consisting of a single cell. 



Vascular. — Containing blood-vessels. 



Vermiform. — Like a worm. 



Vertebrata. or Vertebrate Animals. — The highest 

 division of the animal kingdom, so called from the 

 presence in most cases of a backbone composed of 



