Comparative Anatomy - ZOO 420 2(1+1) Zoology Department Dr. Elsayed Younis

The skin of Amphibians 1- Epidermis : stratified squamous epithelium rest on a basement membrane. Basal layer known as germinative or malpighian layer while the most outer layer is horny or stratum corneam. 2- Dermis : built up of a connective tissue differentiated into two distinct layers: A- The outer one known as spongy layer and formed of areolar connective tissue

- Mucus gland: secretes mucus ( small in size but numerous) B- The inner (called compact layer) formed of fibrous C.T. arranged in parallel to the surface, but some them are perpendicular to it forming a vertical strands. Skin derivatives 1- Soft structures :- - Mucus gland: secretes mucus ( small in size but numerous) - Poisonous gland: produces venom ( large in size but few) - Melanophores: contains black pigments in form of granules responsible for the color of the skin. 2- Hard structures :- Absent

1- Epidermis : stratified squamous epithelium rest on The skin of Reptiles 1- Epidermis : stratified squamous epithelium rest on a basement membrane. Basal layer known as germinative or malpighian layer while the most outer layer is horny or stratum corneam. 2- Dermis : built up of a connective tissue differentiated into two distinct layers: A- The outer one known as spongy layer and formed of branched yellow fibers

arranged in parallel to the surface. B- The inner (called compact layer) formed of white fibers arranged in parallel to the surface. Skin derivatives 1- Soft structures :- - Scent glands or Pheromone secreting cells - Chromatophores : contains pigments (black or melanin; yellow or xanthophores and iridophores or colorless guanine) responsible for the color of the skin. 2- Hard structures :- hard scales ( overlapping scales; not overlapping scales; folding scales and side to side scales )