[390] 
THE 
NASAL RHEGION IN EHUTAEHNTIA. 
BY A. B. MACALLUM, B. A., HiaH ScHooL, CoRNWALL, ONTARIO. 
The original object of the present paper was a description of the 
Organ of Jacobson as it obtains in Eutaenia. During the progress 
of my studies in that direction, however, new features and modifica- 
tions of previously described structures in the nasal cavity, lachry- 
mal duct, and on the palatal surface, were observed, and I felt 
compelled, in consequence, to abandon that limit, and to include 
below a description of the whole Nasal Region. 
The material for study consisted of a series of sections from an 
embryo-head, 6 mm. in length, of Eutaenia sirtalis, and several 
series from the nasal region of adult forms of the same species. 
In addition to these, I have examined many of the parts in ques- 
tion in fresh state in salt solution, and also when macerated. A 
number of macerating reagents were employed, but treatment with 
Miiller’s Fluid and subsequent staining with an alcoholic solution of 
HKosin, gave the best results. 
I must here express my sincere thanks to Prof. Wright for the 
kind advice and assistance received from him on points of this work, 
and especially on the Organ of Jacobson, the structure of which I have 
studied with him in his own laboratory. I am also indebted to him 
for several of the drawings accompanying this paper. 
The roof of the mouth in the adult possesses several strongly 
marked ridges and depressions. Of the former there are two on 
each side of the middle line, that over which the maxilla lies being 
the most prominent throughout. It runs parallel with the lip, and 
does not unite with its fellow of the opposite side in front. The 
palatine ridges commence some distance behind, are parallel to each 
other, and bound a depressed palatal surface. Between the maxillary 
and palatine ridges of each side lies another longitudinal depression 
whose surface is striated, the course of the striation being obliquely 
