CHAP. VIII.] 



CAUDATE NERVE-VESICLES. 



213 



together in situ. Hence some are spherical, others ovoidal, or 

 ellipsoidal. In some vesicles we find, external to the nucleus, 

 particles of a coarser kind , Fig 55 



which are accumulated in 

 a mass, frequently of a se- 

 milunar form. These are 

 pigment granules; their 

 presence gives a dark co- 

 lour to a portion of the 

 vesicle. Sometimes we 

 find two groups of pig- ( 

 ment granules in one ve- g) 

 side. They are usually / 

 of a reddish or yellowish ' 

 brown colour. 



Another form of nerve- 

 vesicle is characterized 

 by one or more tail-like 

 processes extended from 

 it, and to such nerve- 

 vesicles we may apply the 

 term caudate. They pos- 

 sess the nucleus and nude- tions of the cerebellum. The larger processes are directed to- 

 wards the surface of the organ, b. Another, from the cerebellum. 



OlllS. as in the more Sim- c. d. Others from the post, horn of gray matter of the dorsal 



region of the cord. These contain pigment, which surrounds 



plC form; and Contain One the nucleus in c. In all these specimens the processes are 

 n . more or less broken. Magnified 200 diameters. 



or more masses ot pigment 



which are often of very considerable size. Both the vesicles 

 and their caudate processes vary greatly in size and shape. The 

 largest nerve-vesicles are found among those of this kind. Some- 

 times there is but a single process from a vesicle ; or there 

 may be two, proceeding from opposite sides; or there may be 

 several, extending in various directions. There is great difference 

 in the shape of these caudate vesicles, as may be observed in figs. 

 55 and 56, where different varieties of them have been repre- 

 sented. In point of structure, the caudate processes are exceedingly 

 delicate, and finely granular, like the interior of the vesicle, with 

 which they distinctly seem to be continuous. Such is the delicacy 

 of these processes, that they readily break off; in general, very close 

 to the vesicle. Sometimes, however, one or more of them may be 

 traced to a considerable distance, and will be found to divide into 

 two or into three branches, which undergo a further subdivision, and 

 give off some extremely fine transparent fibres (fig. 56, b), the con- 



Ganglion globules, with their processes, nuclei, and nucleoli; 

 a. a. From the deeper part of the gray matter of the convolu- 



