The Anatomy of Chlamydoselachus 



479 



He was unable to trace this nerve to the brain. In his summary (p. 677) he writes: 

 ''Der Oculomotorius steht mit dem Trigeminus in Verbindung." 



Ziegler (1908) remarks that the 25'mm. embryo of Chlamydoselachus studied by 

 his pupil, Brohmer, was cut in ''eine liickenlose Schnittserie." Ziegler 's account of the 

 cranial nerves of Chlamydoselachus, which is based on Brohmer's studies and some 

 observations of his own, is largely a confirmation of Brohmer's results. Ziegler evidently 

 believes that, in elasmobranchs generally, the ciliary ganglion is closely associated with 

 the profundus nerve, though many authors have emphasi7;ed its relation to the oculomotor. 



In various selachians, one or more 

 small (ciliary) ganglia are related to the 

 oculomotor nerve (Daniel, 1934). These 

 ganglia give rise to nonmeduUated fibers 

 which make up the short ciliary nerve. In 

 Squalus (Norris and Hughes, 1920) the 

 ciliary ganglion is connected by fibers 

 with the oculomotorius, the ophthalmicus 

 profundus V, and the palatinus VII nerves. 

 A review of the literature on the relations 

 of the ciliary ganglion in elasmobranchs is 

 given by Norris and Hughes (1920). 



In Chlamydoselachus the superficial 

 ophthalmic V, according to Hawkes, 

 passes from the Gasserian ganglion side 

 by side with the profundus nerve, which 

 it equals in si?e. It at once passes dorsally 

 and enters the same groove as the oph' 

 thalmicus superficialis VII, with which, 

 however, it does not unite. About as far 

 forward as the external nares, but nearer 

 the median line, it spreads out into many 

 branches which lie immediately under the 

 skin. This nerve apparently contains only 

 cutaneous elements. A somewhat differ- 

 ent account of the same nerve is given by 

 Allis (1923, pp. 210-211) as follows: 



The ramus ophthalmicus superficialis 

 trigemini, as I define this nerve, includes the 

 similarly named nerve of Merritt Hawkes' 

 descriptions and her ramus ophthalmicus 

 superficialis facialis, and these two nerves 

 were completely fused with each other in 

 the two specimens examined, instead of 



Text'figure 118. 

 Reconstruction of the cranial nerves in a 25'tnm. 



embryo of Chlamydoselachus. 

 Ac, nervus acusticus; Cg., ciliary ganglion; D.e., ductus endolym- 

 phaticus; F.Ac, n. facialis acusticus; Ggl.l, Gg!.2, remnants of 

 the ganglionic crest; G!., n. glossopharyngeus; Gl.v., ventral root 

 of the glossopharyngeal nerve; J^.l.v., n. lateralis vagi; Oc, n. 

 oculomotorius; :„, nerve knot in the premandibular cavity; R.bucc, 

 ramus buccalis; R.hy., ramus hyoideus; R.md., ramus mandibularis; 

 R.mx., ramus maxillaris; R.o.s., ramus ophthalmicus profundus; 

 Spr. (I)., spiracle (first gill-cleft); Tr., n. trigeminus; Vg., roots of 

 the vagus nerve; Vg.5., the last branch of the vagus; J.Sp., first 

 spinal gangHon; I.D., first ventral root (of the occipitospinal 

 nerves); II, III, IV, V, second to fifth gill-clefts. 



After Brohmer, 1909. Text-fig. 10. 



