Periostracum

(per-e-os' -trak-nm). In biology, the horny epidermis investing the shells of molluscs. Per i orchitis (per-e-or-ki' -tis). Inflammation of the ti ues surrounding the testicle, especially of the tunica vaginal is testis. P. adhaesiva. a form in which adhesions between formed. the two layers of the tunica vaginal is are Periotic (per-e-o'-tik). I. Situated or occurring around the ear. A term also applied to the petrous and mastoid parts of the temporal bone. 2. Of or pertaining to the region or ti ues immediately about the internal or true ear. P. Periosteal (pere-os/- te-al). Pertaining to the periosteum. P. Bone, the bone formed by the cells of the osteogenic layer of Capsules. Huxley's name for the independent cartilages that appear very early around the otocysts and later become integral parts of the primitive chondrocranium by coalescing with the occipital cartilage. It is not known whether they represent primarily distinct skeletal pieces or merely separate centers of chondrification of a larger mesochymal skeletal piece; probably the latter.