GLOSSARY. 149 



Trige'minal | (L. three at a birth). The name of the fifth pair 

 Trige'mini ) of nerves ; so called because they arise by three 



pairs of roots. 

 Trigo'ne (Gr. a triangle). A small triangular surface in the 



bladder which is devoid of rugae. 

 Trflobita (Gr. treis, three; lobos, a lobe). A group of extinct 



Crustacea, the bodies of which were composed of three lobes. 

 Trionychoi'dea (Gr. trionux, a tortoise ; ddos, shape). A 



group of the Chelonia which comprises the soft or mud 



tortoises. 

 Triploblas'tic (Gr. triploos^ triple ; blastos, a germ). A term 



applied to those ova in which the blastoderm splits into 



three layers. 

 Tri'vium (L. a place where three roads meet). The name 



given to the three anterior ambulacra of the Echinidea, 

 Tro'chal disc (Gr. trochos, anything round, a hoop). The oral 



disc in the Rotifera which is fringed with long cilia. 

 Trochan'ter (Gr. trochanter, a word signifying turning). The 



name given to two processes (major and minor} of the 



upper part of the femur. Also the second joint of the leg 



in the Insecta. 

 Tro'chlea (Gr. trochilia^ a pulley). The name given to that 



part of the humerus which articulates with the ulna, be- 

 cause shaped like a pulley. Also to the fibro-cartilaginous 



ring which is attached to the frontal bone, and through 



which the tendon of the superior oblique muscle of the 



eye passes. 

 Tro'chlear. The name given to the fourth pair of cerebral 



nerves which supply the upper oblique (trochleares) muscles 



of the eyes. 

 Troglody'tes (Gr. troglodutes, one who lives in holes). A 



genus of the Anthropomorpha. 



Tro'phic (Gr. trepho, I nourish). Connected with nutrition. 

 Trun'cus arterio'sus (L. arterial trunk). The part of the heart 



from which in some Vertebrata the arteries spring. 

 Tu'ber annula're (L. annular swelling). Another name for the 



Pons Varolii which see. 



Tu'ber cal'cis (L. swelling of the ankle). The posterior extre- 

 mity of the calcaneum. 

 Tu'ber cine'reum (L. grey swelling). A layer of grey matter in 



the base of the cerebrum. 

 Tu'ber cochleae (L. swelling of the cochlea). The projection of 



the first turn of the cochlea into the tympanum of the ear. 



