THE DEVELOPMENT OF THE OLFACTORY NERVE 



AND ITS ASSOCIATED GANGLION IN 



LEPIDOSTEUS 



CHARLES BROOKOVER 



From Ihc AiKitoinical Laboratory of the Universilij of Arkansas 



SEVE.VTEEX FIGURES 



The writer (Brookover '08) published a preliminary note con- 

 cerning the presence of a ganglion on the olfactory nerve of young 

 specimens of Lepidosteus and in a later paper ('10) gave some 

 additional facts concerning it. Considerable literature has 

 grown up in relation to the nervus terminalis in recent years and 

 there seems no doubt that this ganglion in the embryos is related 

 genetically to the nervus terminalis. ]\lcKil)ben ('11) deals with 

 the nervus terminahs, especially its central relations in the uro- 

 deles, and Herrick ('09) had previously noted its presence in 

 Anura. McCotter ('13) has demonstrated it in adult dog and cat, 

 and Johnston ('13) has described it in embryos of reptiles and 

 mammals. The reader is referred to the bibliographies of these 

 papers for the complete literature. 



With the idea of shedding further light on the structure and 

 possibly the function of this nerve, which is apparently univer- 

 sally present in the vertebrates, we have undertaken to follow the 

 development of the ner\iis terminalis through to its adult struc- 

 ture in Lepidosteus osseus, an important member of the ancient 

 order of Holostei. 



Formerly we had nothing but a miscellaneous collection of 

 embryos and young, but more recently we have had a graded 

 series of embryos procured for us by stripping the eggs and ferti- 

 lizing them simultaneously. It is this same series that Landacre 

 ('12) used in describing the epibranchial placodes of Lepidosteus. 

 The preservation was in fluid of Zenker at intervals of al^out six 



113 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 24, NO. 2 

 APRIL, 1914 



