THE MORPHOLOGY OF THE EYE MUSCLE NERVES 



H. V. NEAL 



Tufts College, Massachusetts 



NINE PLATES AND FOUR TEXT FIGURES 



CONTENTS 



Introduction 2 



1. The eye-muscle nerves as criteria of head segments 5 



2. Technical methods 7 



Histogenesis of spinal somatic motor nerves 



1. General description 11 



2. Protoplasmic connection between muscle and nerve center 16 



3. Genetic relations of protoplasmic connections to cells 32 



4. Genetic relations of protoplasmic connections to neurofibrils 35 



5. The process theory versus the cell-chain theory 41 



6. The growth of the neuraxon 43 



a. The histogenesis of the Rohon-Beard cells 47 



7. The origin of the cells of spinal somatic motor nerves 49 



8. The fate of the cells of somatic motor nerve anlagen 51 



9. The histogenesis of the neurilemma 53 



10. The genesis of the sympathetic anlagen 54 



11. Summary 58 



Histogenesis of the eye muscle nerves 



1. General description 60 



2. Histogenesis of the oculomotor : {a to j) 62 



3. Histogenesis of the trochlear : {a to j) 78 



4. Histogenesis of the abducens : {a to j) 90 



5. The bearing of the evidence upon the head problem 97 



Relationships of the eye muscle nerves 



1. The somitic nature of the eye muscles 98 



2. The relations of the oculomotor 100 



a. Relations to the profundus branch of the trigeminal 100 



b. Relations to the ciliary ganglion 102 



c. Relations to four eye muscles 102 



d. The morphology of the oculomotor: Conclusions 103 



3. The relations of the trochlear 106 



a. Relations to ganglia 106 



Relations to the superficial branch of the trigeminal 107 



b. Relations to a somite innervated also by another nerve 108 



c. The chiasma of the trochlear 109 



d. The morphology of the trochlear: Conclusions 114 



1 



JOURNAL OF MORPHOLOGY, VOL. 25, NO. 1 

 .MARCH, 1914 



