GLOSSARY 669 



axilla. The arm-pit. 



axis (epistropheus). The second cervical vertebra. 



axolotyl. The larval, and sometimes permanent, stage of the salamander Ambystoma. 



Bartholin, glands of. The vulvo-vaginal glands. 



basalia. The proximal elements of the cartilaginous skeleton of the extremity. 



basihyal. The ventral element of the hyoid skeletal arch. 



basilar membrane. The basal membrane of the organ of Corti. 



basilar plexus. A venous plexus in the dura mater which lines the occipital bone. 



basioccipital. The basal portion of the occipital ring. 



basophilic. With affinity for basic dyes. 



Bell's law. The dorsal roots of spinal nerves are sensory, the ventral motor. 



biceps brachii. The arm muscle which flexes the forearm. 



bicuspid. A tooth (premolar) with two cusps. The left atrioventricular valve of the 



heart. 

 bilateral. A tj^pe of symmetry such that one plane, and only one, will divide a body 



into equal halves. 

 biogenesis. Life comes from life, not from the lifeless. 

 biogenesis, fundamental law of. Ontogenesis repeats phylogenesis. 

 blastocoele. The cavity of the blastula. 



blastoderm. The membrane from which the embryo develops. 

 blastopore. The external orifice of the gastrula. 

 blastula. The one-layered stage of ontogenesis. 



body-stalk. The mesodermal bridge which connects the embryo with the chorion. 

 Bowman's capsule. The globular dilatation of an uriniferous tubule enclosing a 



glomerulus. 

 brachium conjunctivum. The superior peduncle of the cerebellum. 

 brachium pontis. The middle peduncle of the cerebellum. 

 branchial bars. The gill or visceral skeletal arches. 

 branchiomerism. The metamerism represented in the visceral arches and pharyngeal 



pouches. 

 broad ligament. The peritoneal fold which supports uterus and ovary. 

 bronchiolus. One of the branches of a bronchus. 

 bronchus. One of the two branches of the trachea. 

 Brunner's glands. Submucous glands of the duodenum. 

 bulbus. The enlarged origin of the aorta. 

 bulbo-urethral glands. Cowper's glands of the urethra. 

 bulbus urethrae. An elongated swelling of the urethra. 

 bursa. A sac-like cavity. 

 buttock. The prominence formed by the gluteus muscle. 



calcaneum. The heel bone. 



calcareous. Composed of lime (calcium) salts. 



callosity. A local thickening of the horny layer of the skin. 



calyx (pi. calyces). One of the recesses of the renal pelvis which encloses the pyramids. 



canaliculus. One of the fine canals which connects bone lacunae. 



canalis reuniens. The duct which connects the cochlear duct with the sacculus. 



cancellous bone. Spongy bone. 



canine tooth. The single cuspid tooth between lateral incisor and first premolar. 



capillaries. The minute vessels which connect arteries and veins. 



capitate. The os magnum of the carpus. 



capitulum costae. The head of a rib. 



cardinal veins. The paired veins which drain head and trunk in lower vertebrates. 



