HUNGARIAN NER1TINÆ. 
461 
For my part, I believe, that Clessin has found the right path, 
and this I follow still further, indeed, by looking on them, far as they 
may live from each other, as one and the same species. This inference 
I draw from the circumstance that the two forms are met with toge¬ 
ther in and about the bath of Püspökfürdő, —- one of the two being, 
however, extinct. Such fossil remains of Neritinae are found in the 
sediments of the bath as well as on a hill called Eontó, near the spring 
of the former. These Aeritinae were grouped by Brusina around two 
types, and named N. Prevostiana forma Adelae and N. Prevostiana 
forma Gizelae respectively. 
I am of opinion that N. Adelae and the typical N. Prevostiana 
are inseparable, and that N. Adelae must be looked upon as an ancestral 
form of that still existing in the Püspökfürdő. In proof of this I need 
not mention anything but the similarly globose shape of the former, 
with no trace of elongation lengthwise and having, as a rule, the last 
whorl subangulated. In respect to marking, these animals, or part of 
them, at least, disclose a similar resemblance to the forms still existing 
at Tata and Püspökfürdő. 
Typically developed individuals of N. Gizelae are easily distin¬ 
guished from the former group by the following characters : — (1) the 
usually smaller size, (2) the higher degree of elongation of the body 
which is more delicately built and never globose, (3) the taller spire, 
(4) the greater or smaller convexity of the columellar area thickened, 
indeed, to a considerable extent at times. 
It is to be recollected that the series ot the extinct Neritinae of 
Püspökfürdő is by no means exhausted by the two forms given by Brusina, 
but that we may find all grades of transition between the two types, 
wether we look at the hight of the spire and the thickening of the colu¬ 
mellar area, or at the form of the body as a whole. No sharp line can 
thus be drawn between the globose forms of N. Adelae and the more 
delicate N. Gizelae. Delicate forms with unthickened columellar area 
show a precise likelihood of N. meridionalis, reasons for which may be 
found by reference to geology, which will be made anon. 
Before this, however, I must insert some remarks on N. pelopon - 
nesia , which differs from N. meridionalis in that the last whorl is checker¬ 
ed by white spots arranged in transverse rows. This is also found in 
some Sicilian forms of N. meridionalis that are quite unable of being- 
distinguished from those living in Greece. They occur there in company 
of black ones, and I have mentioned already that traces of these white 
spots are also seen on the shells of those forms which live in the thermal 
springs of Tapolcza in Hungaiy. I hardly believe, therefore, in any 
