Beiträge zur Entwicklungsgeschichte der Selachii. 369 



that it terminates in a neuromast (Nervenhügel), one would be in- 

 clined to suppose that it simply contains fibres similar to those 

 distributed to the neuromastic canals. But the circumstance that it 

 is distributed solely to the anterior wall of the diverticulum, suggests 

 that it may be of higher morphological importance. The fact that 

 in Mustelus there exists a neuroepithelium in a diverticulum of the 

 spiracle, to which some praetrematic fibres are distributed, is sufficient 

 to indicate a point of contact with the condition I have described 

 in Lepidosteus, and to suggest that similar fibres may have associated 

 themselves with the Ramus oticus. ^^ 



In einer ausführlicheren Arbeit (63) kommt der amerikanische 

 Forscher nochmals auf den Ramus oticus zurück. In dieser Arbeit 

 lesen wir Folgendes: »In Front of the pseudobranch (Lepidosteus, 

 Amia) is the persistent hyomandibular cleft, which has no external 

 aperture (spiracle), but possesses a diverticulum recalling the auditory 

 diverticulum of the same cleft in Mustelus. Unlike that, however, 

 it is surrounded by the cranial cartilage of Polyodon. The cleft 

 and diverticulum contain a long free neuromast (Nervenhügel) sup- 

 plied by a distinct branch of the Ramus oticus VII. It is possible 

 that this sense-organ (represented also in Mustelus) is developed from 

 the fusion of the Ramtis ventralis VII with the epithelium of the 

 hyomandibular pouch in the same way that the neuromasts of the 

 skin result from the fusion of the dorsal branches with the epiblast.« 



Weiter finde ich noch Folgendes über den Ramus oticus von 

 Amia Calva bei Allis (1, 2) und von Laemargus bei Ewart (18) 

 erwähnt. In seiner Arbeit über die Seiteulinie von Amia theilt Allis 

 über den in Rede stehenden Nerv Folgendes mit: »The ramus buc- 

 calis facialis supplies the first thirtheen organs of the infra-orbital 

 line and the ramus oticus facialis the next three (14. 15 and 16). 

 Organs 15 and 16 are always supplied by branches of the ramus 

 oticus facialis. This nerve arises directly from the facial ganglion. 

 It runs upward and outward without entering the orbit, and, piercing 

 the cranial cartilage, issue on the top of the chondrocranium at the 

 extreme anterior end of the diverticulum of the temporal groove. 

 It here separates into three branches, two of which supply organ 15 

 and 16, and one the organ at the upper end of the spiracular canal.« 

 Und in seiner letzterschienenen großen Abhandlung über die cranialen 

 Muskeln und Nerven von Amia sagt er von diesem Nerven: »The 

 ramus oticus facialis, which is simply a brauch of the buccalis, arose 

 on both sides close to the base of that nerve. It ran upward and 



