1. A midline ectodermal depression ventral to the embryonic brain and surrounded by the mandibular arch; when the buccopharyngeal membrane disappears, it becomes continuous with the foregut and forms the mouth. SYN: stomatodeum. 2. The anterior portion of the insect alimentary canal, consisting of mouth, buccal cavity, pharynx, esophagus, crop (frequently a diverticulum), and the proventriculus. [Mod. L. fr. G. stoma, mouth, + hodaios, on the way, fr. hodos, a way]
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sto·mo·de·um or sto·mo·dae·um .stō-mə-'dē-əm n, pl -dea -'dē-ə or -daea -'dē-ə also -deums or -daeums the embryonic anterior ectodermal part of the alimentary canal or tract
sto·mo·de·al or sto·mo·dae·al -'dē-əl adj
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n.
the site of the embryonic mouth, marked by a depression lined with ectoderm from which the teeth develop. The membrane separating it from the foregut breaks down by the end of the first month of pregnancy. Compare proctodeum.
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sto·mo·de·um (sto″mo-deґəm) [stomo- + Gr. hodaios pertaining to a way] an invagination of the surface ectoderm of the embryo during the fourth week, at the point where later the mouth is formed. stomodeal adjMedical dictionary. 2011.