. The biology of the frog. Frogs. THE NERVOUS SYSTEM 28s Both the cord and the brain are surrounded by membranes which are designated by Gaupp as fol- lows : Externally is the dura 7iiatcr, consisting of two layers sepa- rated by a lymph space {i)iterdural space) ; the outer layer of this is pigmented and closely applied to the inner surface of the cranium and neural canal; the inner layer is devoid of pigment and lies close to the brain and cord. Within the dura mater is a thin vascular layer corresponding to the />ia mater and arachnoid of the higher verte- brates ; only here and there do
. The biology of the frog. Frogs. THE NERVOUS SYSTEM 28s Both the cord and the brain are surrounded by membranes which are designated by Gaupp as fol- lows : Externally is the dura 7iiatcr, consisting of two layers sepa- rated by a lymph space {i)iterdural space) ; the outer layer of this is pigmented and closely applied to the inner surface of the cranium and neural canal; the inner layer is devoid of pigment and lies close to the brain and cord. Within the dura mater is a thin vascular layer corresponding to the />ia mater and arachnoid of the higher verte- brates ; only here and there does it present a division. Fig. 79. — The central nervous system of the frog. The roof of the skull and vertebral column re- moved to show the brain and spinal cord, at, atlas, or first vertebra; au, auditory capsule; , brachial enlargement of the cord ; fJni, filum terminale; , proiitic ganglion (trigeminus, or Gasserian ganglion of many authors) ; , lum- bar enlargement of cord; nin (K"), mandibular branch of fifth nerve ; mx ( F"), maxillary branch of trigeminus nerve; my, myeion, or spinal cord; 11a, right nasal sac; na , left nasal bone; , neural canal; , olfactory nerve; oph ( V)t-^ ophthalmic branch of fifth nerve; //, optic nerve. (After Howes.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Holmes, Samuel J. (Samuel Jackson), 1868-1964. New York Macmillan
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfrogs, bookyear1916
