GLOSSARY. 351 



TRO'CHAL (Gr. trocJios, a wheel). Wheel-shaped ; applied to the ciliated disc 

 of the Eotifera. 



TRO-CHAN'TER (Gr. trecho, I run). A process of the upper part of the thigh- 

 bone (femur) to which are attached the muscles which rotate the limb. 

 There may be two, or even three, trochanters present. 



TRO'CHOID (Gr. trochos, a wheel ; and eidos, form). Conical, with a flat base ; 

 applied to the shells of Foraminiftra and Univalve Molluscs. 



TRO'PHI (Gr. trophos, a nourisher). The parts of the mouth in insects which 

 are concerned in the acquisition and preparation of food. Often called 

 u instrumenta cibaria." 



TROPH'O-SOME (Gr. trepho, I nourish ; and soma, bodv). Applied collectively 

 to the assemblage of the nutritive zooids of any Hydrozobn. 



TRTO'OA-TED (Lat. trunco, I shorten). Abruptly cut off ; applied to univalve 

 shells, the apex of which breaks off, so that the shell becomes " decol- 

 lated." 



TU-BIC'O-LA (Lat. tuba, a tube ; and cola, I inhabit). The order of Annelida 

 which construct a tubular case in which they protect themselves. 



TU-BIC'O-LOUS. Inhabiting a tube. 



TU-BU-LAR'I-DA. 



TU-NI-CA'TA (Lat. tunica, a cloak). A class of Molluscoida which are envel- 

 oped in a tough, leathery case or " test." 



TUR-BEL-LA'RI-A (Lat. turbo, I disturb). An order of Scoledda. 



TUR'BI-NA-TED (Lat. turbo, a top). Top-shaped ; conical, with a round base. 



UL'NA (Gr. olene, the elbow). The outermost of the two bones of the fore- 

 arm, corresponding with \hzfibula of the hind-limb. 



UM'BEL-LATE (Lat. umbella, a parasol). Forming an umbel i. e., a number 

 of nearly equal radii, all proceeding from one point. 



UM-BIL'I-CUS (Lat. for navel). The aperture seen at the base of the axis of 

 certain univalve shells, which are then said to be "perforated" or " um- 

 bilicated." 



UM'BO (Lat. for the boss of a shield). The beak of a bivalve shell. 



UM-BREL'LA. The contractile disc of one of the Lucernarida. 



UN'CI-NATE (Lat. uncus, a hook). Provided with hooks or bent spines. 



UN-GUIC'U-LATE (Lat. unguis, nail). Furnished with claws. 



UN-GU-LA'TA (Lat. ungula, hoof). The order of Mammals comprising the 

 Hoofed Quadrupeds. 



UN'GU-LATE. Furnished with expanded nails constituting hoofs. 



U-NI-LOC'U-LAR (Lat. unus, one ; and loculus, a little purse). Possessing a 

 single cavity or chamber. Applied to the shells of Foraminifera and Mol- 

 lusca. 



U'NI-VALVE (Lat. unus, one ; valvce, folding-doors). A shell composed of a 

 single piece or valve. 



U-RO-DE'LA (Gr. oura, tail ; delos, visible). The order of the tailed Amphi- 

 bians (Newts, etc.). 



UR'TI-OA-TING CELLS (Lat. urtica, a nettle). (See Cnidse.) 



VAO'U-OLES (Lat. vacuus, empty). The little cavities formed in the interior 

 of many of the Protozoa by 'the presence of little particles of food, usually 

 surrounded by a little water. These are properly called " food-vacuoles,'' 

 and were supposed to be stomachs by Ehrenberg. Also the clear spaces 

 which are often seen in the tissues of many Ccelenterata. 



VAR'I-OES (Lat. -varix, a dilated vein). The ridges or spinose lines which 

 mark the former position of the mouth in certain univalve shells. 



VAS'OU-LAR (Lat. vas, a vessel). Connected with the circulatory system. 



VE'LUM (Lat. for a sail). The membrane which surrounds and partially closes 

 the mouth of the " disc" of Medusae, or medusiform gonophores. 



VEN'TRAL (Lat. venter, the stomach). Eelating to the inferior surface of the 

 body. 



VEN'TRI-CXE (Lat. dim. of venter, stomach). Applied to one of the cavities of 

 the heart, which receives blood from the auricle. 



