Lizard Descending Pathways 
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Figure 5. Photomicrographs of degeneration in the 8th segment (midbrachial) of lizard spinal cord follow- 
ing a complete hemisection of the first spinal segment (animal TNT; Fink-Heimer stain). (D) Low power 
photo of the ipsilateral spinal gray matter; squares indicate where high-power photos were taken. (A) 
Dorsal horn (DH) : Note the absence of axonal debris. (B) The border between laminae VI and VII: Note 
that lamina VII is filled with axonal, preterminal, and terminal debris; lamina VI contains primarily a few 
degenerating axons-of -passage (arrows). (E) Preterminal and terminal debris can be seen in laminae VI 
and VII; axons-of-passage (arrows) can be seen coursing from lamina VII into lamina X (the dorsal gray 
commissure). (C) The lateral lamina IX group of motoneurons: Note the absence of axonal debris. (F) 
Lamina VIII and medial lamina IX: Note the preterminal and terminal debris. Abbreviations are: dorsal 
column (DC), dorsal horn (DH), lateral column (LC), and medial longitudinal fasciculus (MLF). Re- 
produced from Cruce (1975), Brain, Behavior, and Evolution, with permission of the publisher. 
