16 THE NAUTILUS. 
guiaris, and thus proves to be a Gastrodonta. The shell is thin, 
transparent, somewhat greenish deep horn colored, of the same 
appearance as Z. nitidus Mill., which species it surprisingly resem- 
bles below, while above it appears different by the greater number of. 
whorls. It seems that here we have a “ missing” or connecting link 
between the so-called type of Zonitoides, and its more characteristic 
North American members. 
7. Mrs. Andrews has, of late, again sent me numerous small 
Zonitidae, collected in the mountains of Tennessee and North Caro- 
lina. From these I learned, beside other things, that Zon. andrewsi 
W. G. B., when adult, has very often (or always?) no internal teeth 
at all. Moreover, the shell attains quite a different configuration : 
the last whorl is placed considerably deeper on the penultimate, or 
gradually descends, thus causing the spire to be much more ele- 
vated ; it becomes also deeper and at last somewhat truncate in the 
periphery (perpendicular section) and subangular below, compara- 
tively large, just as we find it in some ligerus, gularis, suppressus. 
At the same time, the base is no more equally rounded, but becomes 
sloping inward, somewhat infundibuliform, the umbilicus is rather 
large, and the striation becomes more crowded and coarse, even so 
that the striz appear to be raised (7. e. the intervals) in place of 
impressed, as they are on the inner whorls. The whole shell then has 
quite a different appearance from that commonly known as Z. 
andrewsi, much resembling the description and figure of Zon. placen- 
tulus Shuttl. Gin W. G. Binney’s Manual, p. 222). The whorls are. 
fully 9 or more, the diameter 7-7°5 mill. It was somewhat difficult 
to state these relations, as I had, though, a good number of speci- 
mens, no complete series from one locality at disposition. There is 
no doubt, to say no more, that many such examples have been 
taken for Zon. placentulus. And, as a striking proof of this, I have 
in my collection four specimens from the mountains of North Caro- 
lina received as Zon. placentulus, years ago, from a conchologist who 
studied those land shells; they show more or less the characteristic 
features noted above, and one of them has a distinct row of denti- 
cles denoting it unmistakably as Zon. andrewsi. 
8. As with the preceding, it is with Zon. significans Bld. Only the 
younger examples, i. e., those commonly found in collections under 
this name, have the teeth, two series of two, as a rule. In older 
specimens, of 5-6 mill. diam., they are no more formed, or only 
occasionally one or another, and then the shells have the characters 
