NEEVES OF THE DOGFISH 387 



border of the ventral rectus muscle. Farther laterally, near the 

 eyeball, occurs another ganglion (ganglion 7) from which the nerve 

 passes into the eyeball (figs. 5, 7, and 21, gcil.6, gcil.7). This 

 nerve running from ganglion 3 out to the eyeball is what is usually 

 termed the ciliaris brevis. The second branch ventral to gang- 

 lion 3 extends posteromesially along the same small artery, but 

 toward the origin of the latter from the pseudobranchial artery. 

 At the dorsomesial border of the base of the infraorbital trunk 

 (mx.V +buc.VII) a ganglion (ganglion 4) is found on this second 

 ciliary branch (figs. 16 and 21, gcil.4). From this ganglion the 

 ciliary branch runs posteriorly along the ophthalmic artery to 

 the junction of the latter with the pseudobranchial artery, and 

 farther posteriorly finally joining a twig of the ramus palatinus 

 VII (fig. 21). Gast shows ' vascular nerves' in Scyllium which 

 possibly represent in part this palatine anastomosis in Squalus. 

 His infundibular nerve with ganglion in Mustelus seems to be 

 the same nerve. Two or three small ganglia (ganglion 5) in 

 Squalus on the ventral border of the rectus ventralis muscle near 

 the ophthalmic artery are closely related to ganglion 3 (fig. 15, 

 gcil.5). The small nerve from ganglion 6 running anteriorly 

 along the ventral surface of the rectus ventralis muscle was not 

 found in all specimens. When present it passes into a double 

 (or single) ganglion (ganglion 8) imbedded in the oculomotor 

 nerve branch destined to the ventral oblique muscle (fig. 21, 

 gcil.S). Farther anteriorly, near where the third nerve breaks 

 up in the ventral oblique muscle, a few ganglion cells (ganglion 

 9) are found, presumably connected by fibers with ganglion 8. 

 Schwalbe's three ciliary ganglia in Scyllium are evidently ganglia 

 3 (with 3a or 6), 8 (double) and 9. His two ganglia in Mustelus 

 seem to correspond to ganglia 3 and 8. 



The writers would not be understood as laying much stress 

 upon homologies between the ciliary ganglia of different species. 

 There is too much individual variability to insist upon homolo- 

 gies based merely upon the situation of ganglionic masses. 



The ciliary plexus in Squalus thus consists fundamentally of 

 ganglionic masses in the orbit, related by non-medullated fibrous 

 tracts to three distinct nerves: oculomotorius, ramus ophthal- 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 31, NO. 5 



