274 loi'RNAI. OF CoMPAKA'ri\"K N KUK()I,<)<;^ . 



The glosso-pharyngeal nidulus is composed of a close 

 aggregate of small pyramidal cells, among which a few fusi- 

 form cells are scattered. The fusiform cells are mostly con- 

 fined to the caudal portion. The pyramidal cells are quite 

 irregular in outline. In hasmatoxylin and in aluminium sul- 

 phate cochineal preparations, these cells are densely stained, 

 and each one presents a densely stained nucleus, within 

 which is a densely stained nucleolus. This nidulus is abund- 

 antly supplied with Deiter's corpuscles. 



Nidulus of the Pneumogastric Nerve (Plate XVIII, Fig. 

 i6). — Anatomically, the nidulus of the tenth nerve is some- 

 times distinct from the nidulus of the ninth nerve and some- 

 times not. Histologically, it is always distinct. It lies 

 caudad to the nidulus of the glosso-pharyngeal nerve, and, 

 usually, does not extend so far dorsad as that nidulus does. 

 Like the above nidulus, the pneumogastric nidulus is elon- 

 gated, with its major axis parallel to the longitudinal axis of 

 the metencephalon. This nidulus is not quite so wide as the 

 nidulus of the ninth nerve. 



The pneumogastric nidulus is composed of lax-ge, typical, 

 irregular gibbous cells, which present a strong contrast to 

 the small pyramidal cells of the glosso-pharyngeal nidulus. 

 In hfematoxylin and in aluminium -sulphate cochineal prepa- 

 rations, these cells are densely stained, and each one presents 

 a large, clearly stained nucleus, within which is a densely 

 stained nucleolus. This nidulus is well supplied with 

 Deiter's corpuscles. 



Nidulus of the Spinal Accessory Nerve (Plate XVIII, 

 Fig. i6). — Immediately ventrad of the nidulus of the pneu- 

 mogastric nerve, and extending from the nidulus of the 

 glosso-pharyngeal nerve caudad into the myelon, there is a 

 narrow, elongated cluster of cells. This cell cluster is sup- 

 posed to be the nidulus of the spinal accessory nerve. This 

 nidulus is composed of large, irregularly arranged, pyramidal 

 cells, which are larger than those of the glosso-pharyngeal 

 nidulus. In haematoxylin and in aluminium-sulphate cochi- 



