OF SOUTHERN INDIA. 25 
known as Rostellaria.* Excluding Pterocera, to which usually the more inflated shells 
with a broad digitate wing are referred, the remainder of the Liassic and Jurassic spe- 
cies of the Azra are generally, since the publication of Morris and Lycett’s “ Fossils 
of the great oolite,”’ described under the generic name Alaria. The most recent publica- 
tion on this pointis the supplement to D’Orbigny’s ‘ Paléontologie Francaise,’ Tom. 
III. Gastropoda. Piette, who undertook the description of the StpHonostomata, res- 
tricts the genus Alaria to those species which have no posterior canal and generally a 
narrow wing: Chenopus (Aporrhais) to others with a posterior canal and broader and 
less digitate wing. Pictet very justly remarks (Mat. p.1. Pal. Suisse, 3me. Ser. 
p- 588 etc.), thatit is impossible to keep up this kind of distinction; but he acknow- 
ledges certain peculiarities in the Jurassic species only, and to these he would restrict 
the name Alaria, placing all the other cretaceous forms under Aporrhais. This, 
however, cannot stand, as we shall have occasion to notice further on, although we 
fully agree with Pictet’s views in general, and have, therefore, endeavoured to shew 
the similarity in the fossil forms by adopting the family name Azara. 
I have myself referred the largest number of the species of the same group, 
from the Alpine Gosau-formation to Alariat. This passing from one extreme to the 
other, and the widely differing controversies of different writers, are sufficient signs of 
the very unsettled state of the question, as to what genera should be accepted. In 
the following description of the species, I have partially adopted Piette’s views, but 
at the same time I have endeavoured to combine with the characters, mentioned by 
the French author, others, which appear of great importance. 
It is well known that young specimens of A. pes-pelicani have no posterior 
canal, and that this becomes developed in fully grown specimens only. But if at 
the same time we examine the shell of the species we have just noticed, we find 
that the callosity, which is secreted in the aperture by the mantle, is totally different 
from what we see in Roséellaria. The body of the animal is very thin, depressed, 
and it is only the margin of the mantle which expands. The anterior canal is in no 
way different from the other digitation of the wing, and the callosity does not extend 
upon the upper surface of the wing, but forms exteriorly a sharp edge. The inner 
lip is strongly thickened, accumulated, not extending beyond the under surface of 
the shell, while, in Lostellaria, the callosity appears to be more equally distributed 
in thin layers over the greater portion of the spire, and not uncommonly over the 
whole shell. Another very marked distinction is the length and the interior space of 
* It is scarcely necessary to notice the unjustifiable application of names such as Gladius, or even Fusus, 
to Rostellaria. Undoubtedly it is not right to ignore old names for the sole reason that they had been neglected 
by subsequent authors. But when these old names have been chiefly applied in a certain loose sense, and never 
had afterwards any certain restricted signification, they are and must be justly rejected. Such is the case 
with Gladius and Fusus, but not with Aporrhais, which had a strict application before Chenopus was introduced, 
probably only because A. pes-pelicani cannot easily be mistaken for any other living species. Gabb in his 
Catalogue (loc. cit p. 109) hastily referred all the cretaceous species, which had been described under Rostellaria 
to Gladius, but in his most recent publication (Paleontology of California, p. 124) he re-adopts, in accordance 
with the generally received views, Rostellaria again. Such uncalled for changes are not to the benefit of 
science. 
+ Sitz. Akad. Wien. 1865, Bd. II, Revision ete. p. 65. 
