MUSTELITS L^VrS. 147 



two portions, — a dorsal and a ventral one. There is not here, 

 however, a strict agreement with the conditions described 

 by Haller in Scyllium. The dorsal root, which arises in the 

 so-called lobus trigemini, separates into three parts, two of 

 which run downward close against the lateral surface 

 of the brain, while the third one turns outward and 

 forward, enters the ramus ophthalmicus superficialis, and 

 forms the lobus trigemini component of that nerve. The two 

 other portions, running almost directly downward, straddle 

 the nearly horizontal ventral portion of the root, which 

 latter portion arises from the " aussere sensorische Oblongata- 

 gebeit '' of Haller's descriptions, that is, from the tuber- 

 culum acusticum. One portion, or bundle, of the fibres 

 of this ventral root continues directly forward, and, 

 joining that bundle of the dorsal root that goes to form part 

 of the ramus ophthalmicus superficialis, forms the tuberculum 

 acusticum component of that nerve. The remaining portion, 

 or bundle, of the ventral root turns sharply downward with 

 the two descending bundles of the dorsal root, the three 

 bundles becoming confused in the sections, and together 

 forming a large stem, which issues from the skull thi-ough 

 the trigemino-facial foramen, a part of it going to form the 

 ramus buccalis and ramus oticus facialis, and a part 

 becoming lost in the facial, or hyoidean, part of the exti-a- 

 cranial trigemino-facial ganglionic complex. 



On this so-called posterior trigeminal root, thus formed of 

 two rootlets, there is no intracranial ganglion whatever, and 

 not even any ganglion cells, excepting just as the roots issue 

 from the skull. Externally to the skull, on both the oph- 

 thalmic and buccal parts of the root, there is a large, 

 separate, and independent ganglion ; but no separate gan- 

 glion is found related to the hyoidean branch of the root. 

 The two rootlets together form the so-called lateral sensory 

 root or roots of all those authors that do not treat them as a 

 part of the trigeminus. It is, however, to be especially 

 noted that both the ophthalmic and buccalis-hyoidean parts 

 of the root receive fibres from two quite distinct regions of 



