OF SOUTHERN INDIA. 213 
all the specimens which have been figured were very imperfect, which does not 
appear very likely. The thickened sutural band provided with very numerous 
strize of growth may add to the peculiarities, which entitle the species to a generic 
distinction, for it must have been in some way connected with a different form of the 
margin of the aperture. Bayle and Coquand (loc. cit.) state, that they received 
the species Lith. Humboldtii with Terr. tetraedra in one and the same piece of rock, 
and besides in company with Gryphea cymbium and other characteristically liassic 
species. The species must, therefore, be struck out of the list of cretaceous fossils, 
where it had been placed by D’Orbigny. 
5.—Turritella, Lamarck, 1799 (H. and A. Adams’ Genera I, p. 351, includ- 
ing TZorcula and Zaria of Gray as sub-genera). Under Twrritella (as restricted) 
those species are here retained, which have a number of equal, chiefly thin, spiral 
strize, and the volutions flattened or slightly convex. Those species are called Toreula, 
the whorls of which are more or less excavated in the middle, and have two spiral 
keels near the sutures, while in Zaria the whorls are provided with a number of sharp 
keels, which are specially strong below the middle of the whorls. Each of the divi- 
sions exhibits certain minor distinctions, but the form of the shell is never markedly 
different, the whorls increasing very gradually in size. In determining a large 
number of fossil species, which are not always well preserved, it is almost impossible 
to fix the limit between Torcula and Turritella, and equally so between this latter 
and Zaria. 'The outer lip is always insinuated, only in different degrees in various 
species, the inner lip is evenly arcuated, and the axis of the shell, though always 
solid, still very thin. 
The determination of the cretaceous species, with respect to the sub-generic 
divisions of Twrritella, is as yet very unsatisfactorily known. So many of them are 
based often upon one or two additional spiral striee of a few whorls, and without any 
reference to the proportions of the same, that we are probably not beyond the 
truth, when we say that of the 76 European species of ZYurritella, quoted by Pictet 
and Campiche, one-third will have to be abandoned. With regard to the critical 
examination of a number of the Alpine species, I must refer to my revision of 
the Gosau-Gastropoda in Sitz. Akad., Wien, 1865, LII, p. 8, etc., and also in 
‘ Jahrbuch Geol. Reichs-Anst.’ Wien, 1863, XIII, pp. 53-54. 
In addition to those already mentioned in the Paléont. Suisse, dme. Ser., 
pp. 318-324, we quote at present the following: Turr. plana, T.? sinistra, 
T. conferta, T. Falcoburgensis, T. ciphyana (vide Binkhorst, Monog. Gast. et Ceph. 
craie de Limbourg, 1861, pt. 1, pp. 33-34 and 77) from the upper cretaceous beds 
near Maestricht. The state of preservation of many of the species is far from satis- 
factory. Zurr. Sarthensis, T. gracilis, T. alternata and T. acicula are mentioned 
as new by Gueranger from the ‘ Grés verts’ of the dept. de la Sarthe (Ess. d’une 
Repertoire Paléont., etc., Mans, 1853, p. 29). Of the three first-named species 
the same author gives figures in his ‘ Album Paléont. etc.’, 1867, pl. 9, but I should 
really be at a loss, how to recognise those species again from such small fragments ! 
Turr. inique-ornata, Drescher (Zeitsch. deutsch. Geol. Gesellsch., 1863, Vol. XV, 
p. 333, pl. 9, fig. 1), a species very much like the Turr. rigida, Sow. from the 
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