26 
Quarterly Journal . 
possession of a thick periostraca, which is often densely 
clothed with hairs arranged in spiral lines. From this fact 
I am of opinion that the radula will be found to vary very 
much from the generic type. Some of our Limneadce are 
introduced from Europe, notably LAmnea peregra (Muller), 
which is found near Hobarton, and I think near Melbourne. 
I should not wonder, also, if we have come by some 
European Physce in a similar way. Nothing has been 
done to elucidate their dental peculiarities, though the 
animals are, of all others, easy of access. We have^ a new 
genera and species, called by me Tatea Huonensis>. The 
examination of the radula would be a delicate piece of 
microscopy, of real value to science. In this and all 
similar instances it would be well to bear in mind the 
importance of the jaw as a specific or generic organ. 
Nerita atrata can be obtained in abundance in Victoria. 
Its radula is very easily examined. It seemed to me 
longer than any of the Trochidcc , though very much of 
the same character. Thalotia , Phasianella, Elenchus, 
Gibbula , Minolta , and Monilea are all nearly unknown; 
and want the hand of some careful microscopist to work 
them out. In Bulla , Kaminea, Bullina , we have no 
radula, but a kind of calcareous or shelly pair of external 
jaws, which hang outside the animal. I am not quite sure 
that this is the structure in Bullina lineata* (Wood), as the 
animal differs from other members of the family in the 
possession of a horny operculum. 
I have merely indicated in the above remarks a line 
of inquiry which may be followed, and I am quite sure 
that with a veiy little trouble a large number ol valuable 
facts will be met with in every way worthy of the records 
of the Microscopical Society, and tending materially to 
enhance their value. 
The following points to be noticed in the Itadula of 
Mollusca may be worth bearing in mind :— 
1. Position in the body of animal, and the form ifc 
assumes therein—Whether tubular or flat, curved or 
straight, coiled or folded ? 
2. In Land and Freshwater Mollusca—The presence or 
absence of a jaw; its form and position when 
present. 
* Tho small striated white Bulla, ornamented with two delicato red spiral 
ines. 
