OF THE NERVUS OOTAVUS. 185 



Fig. 28 B. The section through the middle of this nucleus. Those sections are drawn 



to demonstrate the extensity of the lesion. 

 PLATB XXII. 

 Fig. 28 c. The section through the distal end of the nuclei oliva.res superiores. It 



demonstrates : 



The loss of fibres in the corpus trapezoides and the atrophy of the 



nucleus olivaris superior, at the operated side. The loss .of the stria 



mod ullaris at that side and the loss of fibres of the //aberrirende Seiten- 



strangbiindel" at that side : 

 Fig. 28 i). The section falls through the proximal end of the lesion The same fibres 



are atrophied as in fig. 28 c. 

 Fig. 28 E. The section falls through the genu N. VII. The crossed //aberrirendes 



Seitenstrangbiindel" now has lost a great many fibres and so have the 



surroundings of the crossed nucleus ventralis lemnisci (atrophied itself). 

 Fig. 28 F. The section falls through the fillet. There is atrophy. 



1 in the superficial layer of the fillet at the operated side. 



2 in the nucleus ventralis lemnisci 



3 in the medial bundle ,.,, 



ot the contra-lateral fillet. 

 I in the lateral bundle 



5 in the aberrirendes Seitenstrangbiindel 



The decussatio ventralis tegmenti contains less fibres at the operated side 

 than contralaterally. 



PLATE XXIII and PLATE XXIV. Fig. 26 A E and fig. 27. 



Fig. 26 A E. A series of frontal sections through the medulla 

 oblongata of a pigeon three weeks after the removal of 

 the labyrinth, demonstrating the degeneration of root- 

 fibres. 



Fig. 27. A longitudinal section through the primary/ octavus-nuclei 

 of a pigeon three weeks after the removal of the labyrinth. 

 (These are Marchi-preparations). 



The abbreviations used here are: 



N. ang. N. VIII = nucleus angularis I 



r. lat. N. VIII radix lateralis | nervi octavi. 



r. desc. N. VIII rr radix descendens 1 



r. N. X radix nervi vagi. 

 r. spin. N. V =r radix spinalis nervi quinti. 



C. R. = corpus restiforne. 

 N. N. XH nucleus nervi hypoglossi. 

 n. parvocell N. VIII nucleus parvocellularis nervi octavi. 



A. /'acusticusfeld". 

 r. med. N. V1IL = radix medialis nervi octavi. 



fibr. dors. fibrae dorsales radicis nervi octavi. 

 X = trunc. uied. medial trunck of octavus-root fibres, 

 f. dors. N. VIII systema dorsale uervi octavi. 



f. 1. p. ~ fasciculus longitudinalis posterior. 



n. magno-cellul. N. VIII nucleus magnocellularis nervi octavi. 

 n. cer. nucleus pedunculi cerebelli. 

 N. VII nervus facialis. 

 N. VI ~ nervus abducens. 



