X TABLE OF CONTENTS. 



pp. 184—189. Olfactory organ.— OliactoTy pit. Sclineielerian folds. Eye. 



General developmeut. Hyaloid membrane. Lens capsule. Processus 



falciformis. Auditory Organs. — Auditory pit. Semicircular canals. Mouth 

 INVOLUTION and Pituitary body, pp. 189 — 191. Outgrowth of pituitary involution. 

 Separation of pituitary sack. Junction with infundibulum. Development 

 OF CRANIAL NERVES, pp. 191- -205. Early development of oth, 7th, 8th, 9th and 

 10th cranial nerves. Distribution of the nerves in the adult. The fifth nerve. 

 — Its division into ophthalamic and mandibular branches. Later formation of 

 superior maxillary branch. Seventh and auditor// nerves. — Separation of single 

 rudiment into seventh and auditory. Forking of seventh nerve over hyomandibular 

 cleft. Formation of anterior branch to form ramus ophthalmicus superficialis 

 of adult. General view of morphology of branches of seventh nerve. Glosso- 

 pharyngeal and vagus nerves. — General distribution at stage L. Their connection 

 by a commissure. Junction of the commissure with commissure connecting 

 posterior roots of spinal nerves. Absence of anterior roots. HjT)oglossal nerve. 

 Mesoblast of Head, pp. 206 — 209. Body-cavity and, myotomes of head, — Con- 

 tinuation of body-cavity into head. Its division into segments. Development 

 of muscles from their walls. General mesoblast of head. Notochord in Head, 

 pp. 209—210. Hypoblast of the Head, pp. 210 — 211. The formation of the 

 gill-shts. Layer from which gills are derived. Segmentation of the Head, 

 pp. 211 — 216. Indication of segmentation afforded by (1) cranial nerves, 

 (2) visceral clefts, (3) head-cavities. Comparison of results obtained. 



CHAPTER X. 



THE ALIMENTARY CANAL, pp. 217 229. 



The solid (p,sophagus. — ffisophagus originally hollow. Becomes solid during 

 Stage K. The postanal section of the alimentary fj-aci. — Continuity of neural and 

 ahmentary canals. Its discovery by Kowalevsky. The postanal section of gut. 

 Its history in Scyllium. Its disappearance. Tlie cloaca and anus. — The forma- 

 tion of the cloaca. Its junction with segmental ducts. Abdominal pockets. 

 Anus. The thyroid body. — Its formation in region of mandibular arch. It becomes 

 solid. Previous investigations, llie pancreas. — Arises as diverticulum from 

 dorsal side of duodenum. Its further growth. Formation of duct. The liver. — 

 Arises as ventral diverticulum of duodenum. Hepatic cylinders. Comparison 

 with other types. 21ie suhnotochordal rod. — Its separation from dorsal wall of 

 alimentary canal. The section of it in the irunk. In the head. Its disap- 

 pearance. Views as to its meaning. 



CHAPTER XL 



THE VASCULAR SYSTEM AND VASCULAR GLANDS, pp. 230 217. 



T'he heart. — Its development. Comparison with other types. Meaning of 

 double formation of heart. The general circulation. The venous system. The 

 primitive condition of. Comparison of, with Amphioxus and Annelids. The 



