CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF THE MUSEUM OF 

 COMPARATIVE ZOOLOGY AT HARVARD COLLEGE E. L. Mark, Director, No. 214. 



THE OLFACTORY REACTIONS OF THE COMMON 

 KILLIFISH, FUNDULUS HETEROCLITUS 



■ (LINN.) 



G. H. PARKER 



In a paper on the olfactory reactions of fishes published in the 

 eighth volume of the Journal of Experimental Zoology (1910), I 

 have attempted to show that the olfactory organs of catfishes 

 are stimulated by minute amounts of substance emanating from 

 materials that can '^rve these fishes as food ; in other words, that 

 these organs are distance-receptors by which the fishes can scent 

 out their food much as land animals do. A season at the Biologi- 

 cal Laboratory of the United States Bureau of Fisheries at Woods 

 Hole, Massachusetts, enabled me to repeat these tests on the com- 

 mon killifish, Fundulus heteroclitus, the results of which are given 

 in this paper. My thanks are due to Dr. F. B. Sumner, Director 

 of the laboratory, for facilities kindly provided, and to Commis- 

 sioner G. M. Bowers, with whose permission this article is pub- 

 lished. 



The olfactory apparatus of the killifish consists of a pair of sacs 

 each provided with two apertures, one anterior, and the other 

 posterior. The anterior olfactory aperture is just above the upper 

 lip and dorsal to the angle of the mouth. It is a small roundish 

 opening not unlike one of, the pores of the lateral-line system 

 and is on the summit of a low elevation. The posterior olfactory 

 aperture is an elongated slit somewhat dorsal to the anterior limit 

 of the eyeball. The mouth of the posterior aperture is partly 

 occupied b}^ a valve-like fold of skin. 



If the quiescent head from a freshly killed Fundulus is examined 

 in water, no motion is observable about the olfactory apertures. 



The Journal of Experimental Zoology, Vol. 10, No. 1 

 January, 1911 



