Volume XI. Dece^nber, l8g^. Number ^. 



JOURNAL 



OF 



MORPHOLOGY. 



CONTRIBUTION TO THE STRUCTURE AND DEVEL 

 OPMENT OF THE VERTEBRATE HEAD. 



WILLIAM A. LOCY. 



CONTENTS. 



Pagb 



General Introduction 498 



Need of closer series of specimens, Scope of the work. — Earliest 

 phase of the conception that the head exhibits metamerism. — 

 Goethe, Oken, Huxley, Gegenbaur, Balfour. 



Part I. — Metamerism of the Head. 



I. Basis for the Discussion 503 



(a) Cranial nerves, {b) Mesoblastic head cavities, (c) Segments of 

 the neural tube. 



II. Historical Review^ of the Work on Neuromeres 505 



Von Baer '28, Bischoff '50, Remak '50, Dursy '69, Beraneck '84, 

 Kupffer '85 and '93, Rabl '85, Gegenbaur, Orr '87, Oscar Hertwig '88, 

 Hoffmann '88, McClure '89, Piatt '89, Zimmerman '91, Waters '92, 

 Froriep '92, Herrick '92, Locy '94. 



III. Descriptions of Stages of Acanthias 5x3 



Stages previous to the formation and closure of the neural groove. — 

 Stages after the closure of the groove. 



IV. Supplementary Observations on Other Animals 528 



Amblystoma, Rana palustris, Diemyctylus, Torpedo ocellata, Chick. 



