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Bashford Dean Memorial Volume 



Text'figure 122. 



Nen-Tis collector, consisting of longitudinal strands connecting the ventral rami of certain 



of the spinal nerves, in Chlamydoselachus. 



l.fl.ti., lateral abdominal vein; iiLfi-, pelvic plexus; sp.25,3S, twenty-fifth and thirty-eight spinal nerves. 

 From Daniel, 1934, Fig. 224; after Braus, 1898, Fig. 1, Taf. XUl. 



the dorsal branch of the ventral root could be seen, by the naked eye, running over the 

 dorsal root gangHon, from which it could not be separated; in the succeeding segment the 

 dorsal and ventral roots were joined in the region of the sensory ganghon, and the dorsal 

 branch appeared to arise from the ganglion itself. The spinal nerves here recall the condition 

 of Laemargus, of Bdellostoma, and of Myxine, in that all three have (1) several rootlets for 

 the ventral root, (2) a dorsal branch firom the ventral root which unites with the dorsal 

 root ganglion or wth some portion of the dorsal root. 



The "nervus collector" studied by Braus (1898) in Chlamydoselachus and in a number 

 of other elasmobranchs, consists of one or more longitudinal strands connecting the ventral 

 rami of some of the spinal nerves situated posterior to the pectoral fin and in the region 

 of the lateral abdominal vein. The principal collector nerve of Chlaynydoselachus (Text- 

 figure 122) is plexiform, and consists of a multitude of anastomosing strands together with 

 some branches that end freely. The nervus collector, though variable, appears to be 

 best developed in primitive forms like Chlamydoselachus and Heptanchus (Text'figure 

 123), in both of u^hich the tvv-entyfifth to the thirty-eight spinal nerves take part. The 



Text-figure 123. 

 Nervus collector, connecting the ventral rami of certain of the spinal nerves, in Heptanchus cinereus. 

 ].a., lateral artery; l.a.v., lateral abdominal vein; pl.p-, pelvic pleius; sp. 25,3S, twentj'-fifth and thirty-eighth spinal nerves, 

 From Daniel, 1934, Fig. 205; after Braus, 1898, Fig. 1, Taf. XI. 



