THE EVIDENCE OF THE RESPIRATORY APPARATUS
Branchiæ considered as internal branchial appendages--Innervation of
branchial segments--Cranial region older than spinal--Three-root
system of cranial nerves: dorsal, lateral, ventral--Explanation of van
Wijhe's segments--Lateral mixed root is appendage-nerve of
invertebrate--The branchial chamber of Ammocoetes--The branchial
unit, not a pouch but an appendage--The origin of the branchial
musculature--The branchial circulation--The branchial heart of the
vertebrate--Not homologous with the systemic heart of the arthropod--
Its formation from two longitudinal venous sinuses--Summary 148