Nos. IAND2.] AXATOMY OF SCOMBER SCOMBER. 295 



In Saliiio Haller (No. 33, p. 53) finds the postvagal nerve of 

 his descriptions arising by two ventral roots, which unite inside 

 the cranium to form a single stem. Outside the cranium this stem 

 unites with the first and second spinal nerves, both of which have 

 both ventral and dorsal roots and a spinal ganglion. The trunk 

 so formed is said to innervate the pectoral fin but to send no 

 branch to the hypoglossal region of the fish, that region being 

 supplied by a branch of the vagus. In Esox Haller says the 

 postvagal nerve seems to present the same conditions as in 

 Salmo. In Anguilla he says the nerve is formed of two ventral 

 spinal roots and one dorsal root, and that it possesses a ganglion. 

 The peripheral distribution of the nerve in Anguilla he did not 

 investigate. 



Anguilla may thus present the same conditions as Scomber, if 

 it be assumed that the postvagal nerve of Anguilla lies pos- 

 terior to the cranium instead of issuing through it as it does in 

 Scomber. With the conditions described in Samo and Esox no 

 comparison seems possible from the descriptions given, the hypo- 

 glossal region in those two fishes being said to be innervated by 

 a branch of the vagus. It is to be noted that Vetter says (No. 

 75) that the pharyngo-claviculares of Esox are innervated as they 

 are in Scomber, that is by branches of the Ri. pharyngei inferioris 

 vagi, and that the sternohyoideus is innervated by "die vereinigten 

 ersten und zweiten Spinalnerven, genauer den R. anterior 

 derselben." Both the pharyngo-claviculares and the sternohyo- 

 ideus muscles of Aviiurus are said by ]\Ic]\Iurrich (No. 49) to be 

 innervated by branches of the first, or first and second spinal 

 nerves. 



In the Cyprinidse the postvagal nerve arises, according to Haller 

 (No. 33), by a single ventral root. This root is joined first by 

 a dorsal root, which Haller considers as the hypoglossal part of 

 the vagus, and then by a large root coming from the so-called 

 " Trigeminus-Komplex " ; the three roots united forming the ac- 

 cessorius Weberi of the fish, on which a ganglion is formed. The 

 trigeminus component of this nerve is said to arise partly from 

 the trigeminal ganglion of its own side of the head, and partly 

 from the corresponding ganglion of the opposite side. As the 

 stem formed by these two roots united passes backward, it is said 



