GLOSS AH Y. 295 



Tegulte. Scales, one on each side, attached to the mesothorax of 



the Lepidoptera. 

 Teleology. The doctrine of final causes, or, the indication of 



design and purposiveness. 

 Telson. The last -segment, or the appendage of the last segment, 



of the abdomen of certain Crustacea. 

 Tentacula. Prehensile organs of the Ccelenterata, and especially 



of the Hydroida. 



Teratology. The study of abnormal forms or monstrosities. 

 Terebra. The boring-organ of insects. 

 Tergal. Eelating to the back. 

 Test. The shell of Mollusca or of Eehinoidea ; also the tunic of 



the Ascidians. 

 Thalerophagous. Feeding on decomposing animal or vegetable 



matter. 



Thaumatogeny. Genesis by miracle. 

 Thelytocous. When a parthenogenetic female produces only 



female offspring. 

 Thermlgenous. Generating heat. 

 Thomia. The sharp edge of a bird's bill. 

 Thorax. The chest, the upper or anterior part of the trunk. 

 Tibia. The shin-bone of mammals, in birds the drumstick. In 



insects it is the fourth joint of the legs. 

 Tornaria. The larval form of Balanoglossus. 

 Trachea. The wind-pipe. In insects and their allies the trachea 



are tubes subservient to respiration. 

 Trichocysts. See Nemafocysts. 



Trochal disk. The wheel-shaped ciliated organ of a Rotifer. 

 Trochanter. A process of the upper part of the thigh-bone. In 



insects it is the second joint of the leg ; but it appears to have 



no separate motion distinct from the femur to which it is at- 

 tached. 

 Trocha-ntin. A small movable piece of the exoskeleton of insects 



placed on the outer part of the coxa. 

 Trochosphcera. A larval form of Mollusca where the head is 



girdled with a row of cilia which ultimately becomes the velum. 

 Trophi. The parts of the mouth concerned in feeding. 

 Trophosome. The "assemblage of zooids" in the Hydrozoa 



"destined for the nutrition of the colony." 



