Pharyngeal fold and non-follicular tonsil of S. camelus. The ventral (Pfv) and dorsal (Pfd) surfaces of the pharyngeal fold are lined by a non-pigmented, non-keratinised stratified squamous epithelium (E) and separated by a layer of loose connective tissue (Ct). The lymph nodules (Ln) and inter-nodular lymphoid tissue (Ilt) are associated with simple, branched, tubular mucus-secreting glands (Gl) in the ventral surface of the fold and constitute Lymphnoduli pharyngeales. In the dorsal surface the lymphoid tissue is situated in the Lamina propria directly below the epithelium (non-follicular tonsil) which in places is very thin (arrow). Simple, tubular mucus-secreting glands and occasional simple, branched, tubular glands are present on the dorsal surface. Blood vessel (Bv). Bar = 400 μm.