368 PRINCIPLES OF ANIMAL BIOLOGY 



Berengario {her' en gah' ri o). Italian anatomist and surgeon in University of 



Bologna, in the sixteenth century. 

 Biconcave {hi' Icon have'). Having the centnun hollow both in front and behind; said 



of vertebrae. 

 Bidder's canal {bid' derz ka naV). A longitudinal tube near the median border of the 



kidney of certain Amphibia; into it the collecting tubules open. 

 Bilateral symmetry {hi lat' cr al sim' me iri). An arrangement of the parts of an 



object or animal body such that the halves on opposite sides of a certain plane are 



mirrored images of each other. 

 Bile (bile). The fluid secreted by the liver in vertebrates. 

 Bile duct {bile' dukt'). The tube through which bile is discharged into the intestine. 



Binomial (hi no' mi al). Consisting of two names or terms. Applied to the system 

 of nomenclature by which each species is given two names, one for the getms, the 

 other for the species. 



Biogenetic law (bi' o je neif ik law'). The doctrine that animals in their embryonic 

 development repeat the evolutionary history of the race. 



Biology \hi oV o ji). The science of life and of living things, whether plants or animals. 



Bionomics {hi' o nam' iks). The study of the relation of organisms to the environment. 



Biota {hi o' ta), The animals and plants of a given area or of a given period of time. 



(See faima and flora, both of which are comprised under the term biota.) 

 Blainville, Henri Marie Ducrotay de {hlaisi veeV). French naturalist, 1777-1850. 

 Blastocoele (bias' to seel). The hollow interior of a blastula. 



Blastophaga (bias tof a ga). A genus of wasp-like insects of the order Hymenoptera, 

 certain species of which dwell in figs. 



Blastopore {bias' to pore). The opening through which the archenteron of an early 

 embryo (gastrula) communicates with the exterior. 



Blastostyle (bias' to stile). The central cellular core of a gonangium. 



Blastula {bias' tu la). An early developmental stage, consisting of a hollow ball of 



cells. 

 Bolina hydatina (bo W na hi dot' i 7ia). A species of ctenophore. 

 Book gill {hook' giV). See book lung. 

 Book lung {book' lung'). A respiratory organ composed of flat sheets joined together 



like pages of a book, found in spiders. 

 Botryllus (ho tril' lus). A colonial marine animal belonging to the subphylum Tuni- 



cata. It lives attached to leaves or other flat surfaces. 

 Bougainvillea ramosa {boo' gaN oil' le a ra mo' sa). A species of marine hj'droid. 

 Bowman's capsule {ho' manz kap' sule). The expanded end of a kidney tubule, in 

 which a glomerulus is located. 



Brachiopoda {brak' i op' o da). A group of marine animals of uncertain rank or 

 relationship. They have a bivalve shell, the two halves of which are unequal. 

 Sometimes placed in a phylum with the Bryozoa and Phoronidea. 



Bract {hrakt). One of the covering (protective?) members of a siphonophore colony. 



Branch {branch). Any one of four major groups of animals in Cuvier's early classifi- 

 cation. 



Bronchus {brong'kus) {pi., bronchi). One of the two main branches of the trachea 

 in many vertebrates. 



Browse {browz). To eat the twigs of bushes or trees. 



