OF SOUTHERN INDIA. 183 
When the callosity of the inner lip has been removed, there appear on such 
imperfect specimens some spiral strive or plaits, which have also been noticed by 
Prof. Pictet in J. truncata (loc. cit., Fig. 4b). Another point worthy of notice 
is, that the inner space of the whorls becomes posteriorly narrower or perfectly 
filled up with shell-mass during the process of growth of the animal, and the 
consequent increase of whorls. This is the reason that the section of the aperture 
is so much smaller in imperfect specimens, than is the real aperture in perfect shells. 
Exactly the same thing can be very often observed in Acteonella (vide same Plate, 
Fig. 10). 
Locality. —Comparapolliam in the Trichinopoly District ; a rare shell. 
Formation.—Arrialoor group. 
XLV. NERINEA, Defrance, 1825. 
(Vide p. 177.) 
1. NeERInEA IncAvAtTa, Bronn, Pl. XIV, Fig. 2. 
1836. Nerinea incavata, Bronn, Tahrb., p. 553, Pl. VI, Fig. 22. 
1843. N. incavata et cincta, Miinst. Golf. Petref. Germ. III, p. 45, Pl. 177, Fig. 1; and Pl. 176, Fig. 12, 
1852. N. eadem, Zekeli, Abhandlungen der Geol. Reichs-Anst. Wien, vol. I, pt. II, p. 36. 
1853. N. eadem, Reuss, Sitzungsb. Akad. Wien, vol. XI, p. 891. 
1865. WN. incavata, Bronn; Stoliczka, ibid, vol. LII; Revision der Gosau-Gast., p. 31. 
NV. testa subcylindrica, perlonga; anfractibus rectangularibus, ad medium ex- 
cavatis, in guntoribus ad suturam anteriorem crenulatis, in adultioribus nonnunquam 
paulo tumescentibus, levigatis; fascia suturali angusta; apertura angulata, sex 
plicis inequalibus instructa; dwabus in columella solida positis, duabus in labio posteriori 
atque duabus in labro ; plica anterior: semper multo fortiore quam posteriori ; canali 
brevi, recurvo. 
Height of one whorl : its width (considered as 1:00) .., ve =0'39 — 0°40, 
The shell begins its growth with an angle of from 15—20 degrees. After some 
time, when the number of whorls increased to about 10—15, the angle decreases 
to 10 degrees, and still farther on the shell becomes almost cylindrical. The total 
number of whorls is in larger specimens 50—60. Allof them are concave about the 
middle, and when young, the anterior margin along the suture is often crenulated : 
older specimens have the whorls quite smooth, only with S-form curved strize of 
growth, perceptible below the narrow sutural band. 
The aperture is rectangular with six folds, two respectively on the solid colum-- 
ella, the posterior portion of the inner lip and the outer lip; the anterior or lower 
fold is in each case much stronger than the posterior or upper. In cases where the 
aperture is preserved, all the folds, except the anterior columellar, are seen to have 
become obsolete. 
This species was first described by Bronn, from Transylvanian specimens, of 
which some years ago Mr. Stur, of the Austrian Geol. Institute, collected a very 
fine series. On account of these materials, I have pronounced Mimster’s NV. cincta 
