446 CRETACEOUS GASTROPODA 
APPENDIX, A. 
The progress of research makes it necessary that frequent additions and corrections should be 
made in Natural history publications, and the opportunity of effecting these should never be lost. 
Although little more than a year has elapsed since the publication of the first four Fasciculi 
of the cretaceous Gastropoda of South India, and only a few months since the succeeding portions have 
been set in type, still the additions, or rather corrections, are comparatively rather numerous. These 
are, however, to a large extent such as add much to the value of the work, being essential to its 
completeness, so far as this can be attained at the present date, from materials, relating to the 
South Indian cretaceous Gastropoda, anywhere available for examination. 
The reasons which necessitate these corrections are mainly three-fold; firstly, I have no hesitation 
in saying, due to an occasional oversight on my own part, which, however, is considerably palliated 
by the other two causes, namely, the inaccessibility of references and of original materials for 
comparison. It is only since the first four fasciculi have been issued that we have obtained some 
of the most important old works bearing on the history of Conchology, as, for instance, those of 
Aldrovandus, Argenville, Klein, Adanson, Montfort, and others. Of newer works we. have 
received Sowerby’s Genera, Troschel’s ‘ Gebiss der Schnecken,’ the American Journal of Conchology, 
of which three volumes are nearly completed, and a large number of periodicals containing valuable 
conchological papers. Of palxontological works not many have been lately published relating to this 
branch ; I may mention Guéranger’s “ Album paléontologique,”’ the XI livraison of Eichwald’s 
“ Tethea Rossica ;”’ Fraas’ account of Palestine in the “ Wiirtembergische Jahreshefte,” the “ Paléon- 
tologie” of Tchihatcheff’s “Asie Mineure,” some of the Catalogues of the “ Smithsonian Miscel- 
laneous Collections,” and a few others. 
In describing the first portion of the South Indian cretaceous Gastropoda I had repeatedly 
cause to mention the difficulty accompanying the identification of some of the species described 
and figured by Prof. Forbes. A large part of Forbes’ materials were procured by Messrs. Kaye 
and Cunliffe in the neighbourhood of Pondicherry, from which locality we had only very few 
specimens, and many of them not even in an equally good state of preservation as those from 
the older collections. It is natural that, when descriptions are taken from imperfect specimens, 
they must remain imperfect, and can be completed or corrected only whenever better materials have 
been procured. But when the descriptions contradict the figures, or one does not sufficiently express 
what may be seen in the other, and besides when the figures are not very good, it is almost 
impossible to be certain of any specific identification. The est and zon est have almost equal chances 
of probability, and with the greatest caution mistakes, or rather inaccurate interpretation of figures, 
are sometimes unavoidable. I felt, as already stated, this uncertainty as to several identifications in 
the first part of the Gastropoda very much, and at the same time I saw that, as soon as my examin- 
ation had extended to the more minute forms of the ProsoprancuiaA Crenoprancuiata Hoxostomata, 
the doubtful cases would considerably increase. Upon the representation of the Superintendent of 
the Geological Survey and through the liberality of the Government this has happily been avoided. 
I was permitted to proceed to Europe not only to examine Prof. Forbes’ original collection, which 
had been presented by Messrs. Kaye and Cunliffe to the London Geological Society (which Society ably 
supported my endeavours), but I was at the same time authorised to visit the principal Museums 
of Europe, and collect such data and information as I might think necessary for the improvement 
and completeness of this publication. As far as time, circumstances, and other important duties 
permitted, this has been satisfactorily done. It is seldom that an author in writing a monograph 
upon a palzontological subject, of which others had previously treated, can enjoy such an opportunity 
of examining all the original specimens of his predecessors as I did. The liberality of view which 
considered these examinations a part of ‘duty’ shows the appreciation of Science on the part of 
the Government of India, and their earnest desire to support and advance such enquiries. 
