B baccate a. [L. bacca, berry] Berry-like in appearance; bacciform. bacillary a. [L. bacillum, little stick] Rod-shaped, or consisting of rod-shaped structures. bacillary band (NEMATA) A modification of the hypodermis | B baccate a. L. bacca berry Berry-like in appearance bacci-form. bacillary a. L. bacillum little stick Rod-shaped or consisting of rod-shaped structures. bacillary band NEMATA A modification of the hypodermis consisting of glandular and nonglandular cells. bacillary layer see brush border bacilliform a. L. bacillum little stick forma shape 1. Rodshaped. 2. ARTHRO Insecta In certain male Diptera refers to a pair of sclerites in the postabdomen joining the hypandrium and epandrium. back n. . baec the rear or dorsal part The dorsal or upper surface. back-cross A cross between a heterozygote and one of its parents. back-mutation The reversion by mutation of a mutant gene to the form from which it was derived. bacteremia n. Gr. bakterion small rod haima blood The presence of bacteria in the hemolymph or blood of invertebrates without production of harmful toxins or other deleterious effects. bacteriophagous a. Gr. bakterion small rod phagein to eat Feeding on bacteria. baculiform a. L. baculum stick or rod forma shape Appearing rod- or staff-like. baculite n. L. baculum stick or rod MOLL Cephalopoda A straight shelled ammonite extinct at the end of the Cretaceous Period. baenomere n. Gr. bainein to walk meros part ARTHRO Insecta The leg-bearing thoracic segment. baenopoda n. Gr. bainein to walk pous foot ARTHRO Insecta The thoracic legs. 110 Maggenti and Gardner baenosome n. Gr. bainein to walk soma body ARTHRO Insecta The thorax. Baer s disc platy Trematoda In Aspidogastrea the large ventral sucker. see opisthaptor. bailer n. F. baille a bucket ARTHRO Crustacea An exopod of the maxilla of crayfish and lobsters that functions in regulating the flow of water in the gill chamber scaphog-nathite. balanced lethals Heterozygotes in which a gene mutation or chromosome structural change occurs that blocks normal development and is fatal before sexual maturity. see lethal factor. balanced load A term describing a decrease in the overall fitness of a population due to the .