2i6 Ciiicinnali Society of Natural History. 



22. Z. dcmissus Binney. The true deinissus is not uncom- 

 mon here. Mr. W. G. Binney, in Bulletin 28, before cited, 

 gives a very careful enumeration of the characters common 

 to'this species and Z. /ijrcrus. The student who reads the 

 technical descriptions prefacing his general remarks on these 

 species, will find them practically alike, save in the number of 

 whorls. The group of shells composed of dei)iissus, ligenis, 

 acerrus, and one or two forms that I have so far been unable 

 to refer to either, is a very closely-allied one, and if the 

 view of Mr. Binney is correct, and acerrus is but a large 

 variety of demissus, it leaves the alliance still more pro- 

 nounced. I have collected the typical deinissus in Ohio, Ken- 

 tucky, Tennessee, North Carolina, Texas, and Florida. It is 

 rare in Ohio and the latter State. The most constant dififer- 

 ence between this shell and ligertis is its more solid texture, 

 and the thickening on the last half or one-third of the base of 

 the body whorl. This is often (juite entirely wanting in 

 ligerus. The second difference is in the greater average 

 depression of the spire in demisstis. 



An infallible test by which the collector who gathers and 

 cleans his own specimens may be guided, is the peculiar 

 aroma of ligcrus when dropped into hot water. I have never 

 cleaned a living shell of this species, from any locality, that 

 failed to thus personate itself. It is so pronounced and so 

 constant that it is curious this characteristic has not been 

 noticed by writers. 



As the writer of this article is making a special study of 

 the variations of the Zonites group, he will be most happy to 

 correspond with other collectors of them in any part of the 

 United States, and to exchange notes and specimens. This 

 genus, if such it is, presents the problem of variation in its 

 best form, and furnishes" abundant material. As the true 

 object of the collector should be to make his cabinet as in- 

 structive as possible, the readiest method of attaining this 

 end is to accumulate authentically located varieties of recog- 

 nized species, and large series of the same species, for thus 

 only can this object be accomplished. A collection of finely- 

 prepared specimens, so arranged, is now as rare as it is valuable. 

 Tlie collector has been too often like the book-maker, led on 

 by the fine rage for " species." It is time the more philo- 

 sophical and reasonable method should predominate. 



