Strong, JoJinston on Nerves of the Sturgeon. 171 



The ventro-lateral tracts of the medulla appear to be made 

 up of the neurites of commissural and tract cells, as has been 

 described in the spinal cord of Selachians and Teleosts. The 

 smaller number of the fibers of the fasciculus longitudinalis pos- 

 terior come from the central diffuse nucleus of the thalamus, 

 the greater number from the motor cells of the ventral horn 

 along the course of the fasciculus in the medulla. Especially 

 interesting is the statement that "it gives immediate origin to 

 the Vlth., to the larger part of the ventral root of the Vllth., 

 to the whole of the ventral roots of the IXth. and Xth., and 

 to the Xllth. nerve. A part of the ventral root of the Vllth., 

 all of the ventral Vth., as well as the IVth. and Illrd., arise 

 from cells lying in the latero-dorsal portion of the ventral horn 

 whose neurites pass more or less directly out into these roots 

 without entering the fasciculus longitudinalis posterior." 



A considerable part of the sensory portion of the trigem- 

 inus after it enters the medulla descends as the spinal V and 

 principally terminates in an enlargement of the dorsal horn of 

 the cord at the point of transition from cord to medulla (nucleus 

 funiculi). The spinal V also receives contingents from the IX- 

 X group as described by Strong and Kingsbury. The larger part 

 of the fibers of the sensory Vth. (deep portion), however, en- 

 ters the tuberculum acusticum where they form a distinct bundle 

 running both forward and backward. The descending portion 

 of the fibers of the Vth. entering the acusticum become arcu- 

 ate fibers and most of them, possibly all, reach the opposite 

 side of the medulla. This is a remarkable course for direet root 

 fibers of the V, it may be remarked here, and should rest on a 

 firm basis of observation. The ascending portion of the deep 

 Vth., enters a nucleus at the anterior end of the medulla which 

 is immediately continuous with the body of the cerebellum. 



A part of the fibers of the Vlllth. end in relation to the 

 Zwischenzellen of Goronowitsch, the remainder, together with 

 the lateral line roots, also form ascending and descending bun- 

 dles. One portion of the descending fibres (called the spinal 

 Vlllth.) partly terminates in the nucleus funiculi and partly in 

 a smaller nucleus mesad of it ; the remainder of the descend- 



