BLA- 



35 



BON- 



worms, which remains unchanged 

 through spermatogenesis (zool.}. 



blastopore (blas'topor) n. [Gk. blastos, 

 bud ; poros, passage.] The cavity 

 leading into the archenteron of the 

 gastrula (etnb.}. 



blastosphere (blas'tosfer) n. [Gk. 

 blastos, bud ; sphatra, globe.] The 

 blastula, a hollow ball of cells (emb.}. 



blastostyle (blas'tostll) n. [Gk. blastos, 

 bud ; stylos, pillar.] In Hydrozoa, 

 a columniform zooid with mouth 

 and tentacles, or with mouth and 

 tentacles absent, bearing gono- 

 phores (zool.}. 



blastossooid (blas'tozo'oid) . [Gk. 

 blastos, bud ; zoon, animal ; eidos, 

 resemblance.] A larval bud in 

 case of precocious budding in 

 Ascidians (zool.}. 



blastula (blas'tula) n. [L. dim. of Gk. 

 blastos, bud.] A hollow globe of 

 cells, with wall usually one layer 

 thick (emb.}. 



blastulatlon (blas'tula'shun) n. [L. 

 blastula, little bud.] Formation of 

 blastulae (emb.}. 



bleeding of plants, exudation of 

 watery sap from vessels at a cut 

 surface, due to root-pressure (bot.}. 



blended inheritance, mixed race or 

 descent. 



blendling (blgn'dlmg) n. [A.S. blan- 

 dan, to mix.] A hybrid. 



blepharoblast (bleTaroblast) n. [Gk. 

 blepharon, eye-lid ; blastos, bud.] 

 See blepharoplast. 



blepharoplast (b!6f aroplast) n. [Gk. 

 blepharon, eyelid ; plastos, moulded.] 

 A centrosome which is in relation 

 to a motor cell organ, as to the 

 flagellum of flagellates (zool.}. 



blight (bllt) n. [A.S. blaecan, to grow 

 pale.] A disease-producing insect 

 or fungus ; a plant disease (bot.}. 



blind spot, the region of the retina 

 of the eye where the optic nerve 

 enters (anat.}. 



blister (blis'tgr) n. [A.S. blotvan, to 

 blow.] A subcutaneous bubble or 

 bladder filled with fluid ; a plant 

 disease. 



blood (blud) n. [A.S. blod, blood.] 

 The fluid circulating in the vascular 

 system of animals, distributing food- 

 material and oxygen and collecting 

 waste products (phys.}. 



blood cells, cells derived by mitosis 

 from the ordinary mesoderm cells, 

 at first somewhat similar to lympho- 

 cytes ; the primitive haematoblasts 

 (phys.}. 



blood crystals, crystals of haemo- 

 globin, haemin, or haematoidin, 

 which form when blood is shaken 

 up with chloroform or ether (phys.}. 



blood dust, the form in which fat is 

 seen in blood cells, by means of 

 the ultramicroscope (phys.). 



blood islands, isolated reddish 

 patches in the mesoderm in which 

 primitive erythroblasts are found 

 enclosed in a mesodermal syncytium 



blood platelets, colourless bodies 

 about one-third the size of the red 

 corpuscles, and nucleated when the 

 red corpuscles are nucleated (phys.}. 



blood plates, minuteamoeboid proto- 

 plasmic bodies found in the blood, 

 each with a small nuclear-like 

 structure (phys.}. 



blood serum, the fluid or plasma left 

 after removal of the corpuscles and 

 fibrin (phys.}. 



blood vessel, any vessel or space in 

 which blood circulates ; strictly 

 only used in regard to special 

 vessels with well - defined walls 

 (anat.}. 



bloom, a layer of wax particles on 

 the external surface of certain 

 fruits, such as grapes, peaches ; 

 the flower of a plant (bot.}. 



blubber (blub'er) n. [M.E. blober, a 

 bubble.] The fat of whales, lying 

 between the outer skin and muscle 

 layer (zool.}. 



blue timber, a wood disease pro- 

 duced by fungus, causing a bluish 

 discoloration (bot.}. 



body blight, a fungal disease of pear 

 trees (bot.}. 



body cavity, the coelom or space in 

 which the viscera, etc., lie ; it is 

 mesodermal in origin, and is 

 schizocoelic or enterocoelic L in 

 development (anat.}. 



body cell, a somatic as distinct from 

 a germ cell. 



body stalk, a band of mesoderm 

 connecting the caudal end of an 

 embryo with the chorion (emb.}. 



bone (bon) n. [A.S. ban, bone.] Con- 



