266 FISH. [Vol. X. 



very complex relations among themselves and with the ventral 

 root fibers in the ganglion. There are three distinct nerve 

 trunks given off from the ganglion (Fig. 62). The first and 

 largest passes off in a ventro-lateral direction, and corresponds 

 to the ordinary spinal nerve trunk as found in the majority of 

 vertebrates; the second passes in a latero-caudal and some- 

 what dorsal direction, while the third extends dorsally. The 

 second and third trunks are about the same size. Ventral and 

 dorsal root fibers were found in all three (Figs. 54, 57, and 62). 

 In the latero-caudal trunk, the dorsal root fibers bend upon 

 themselves at quite an acute angle to enter the myel through 

 the dorsal root; and in the dorsal trunk, where these fibers 

 would have to bend at a very acute angle to enter the myel 

 through this root, the bending could still be demonstrated. 

 The ventral root divides near the myel, and sends fibers to both 

 the latero-caudal and dorsal trunks, as well as to the ventral 

 trunk. 



The division of these fibers in the ganglion itself to form 

 nerve trunks is an unusual occurrence, although their division 

 just outside of the ganglion is not so infrequent. Schaffer (49) 

 notes and figures a ganglionic division of the ventral and dorsal 

 roots in the Angnis fragilis, and that in this crossing of the 

 fibers there result two bundles, the larger of which, the ramus 

 commimicaiis veniralis, contains the motor elements of the 

 dorsal root ; the more slender bundle, the ramus communicans 

 dorsalis, contains the sensory elements of the ventral root; so 

 that there pass out from the ganglion two nerves. His, in 

 1888, showed that there enter into certain of the cranial nerves 

 fibers which are not ganglionic in their origin, but, from their 

 source, are evidently efferent, or motor, in function, and that 

 in this apparently dorsal root there are found two elements, 

 one of which, the efferent, Minot (30) calls the lateral root. 

 This condition is also said to exist in some of the more cephalic 

 of the cervical nerves; and Minot prognosticates that they may 

 also be found in the spinal nerves as well. Van Gehuchten (14) 

 a few months before the appearance of Minot's paper, had 

 described the presence of efferent, or motor, fibers in the dorsal 

 roots of an embryo chick, confirming what had been stated by 



