OF SOUTHERN INDIA. 67 
former are very numerous and nearly all of equal strength and equally distant, some 
very fine ones being occasionally intermingled between the others. The transverse 
ribs are somewhat stronger and broader, resembling periodical accumulations of 
striee of growth; they are slightly flexuous on the last volutions. The aperture is 
oval, pointed at each end, callose internally. The outer lip is a little expanded 
and thickened, on the margin somewhat reflexed, rounded in front and very thick 
on the outer edge; internally flattened, near the posterior extremity deeply and 
broadly insinuated, and towards the anterior extremity provided with slight denticula- 
tions. The inner lip is callose, apparently not much enlarged and on the apertural 
margin provided with short papille, or partially granulated. The canal is short, 
broad, very slightly bent to the left side (in front view), and widely emarginated. 
The peculiar cancellate ornamentation of the surface, the short, nearly straight 
and widened canal, the broad but shallow insinuation of the outer lip near the 
posterior termination and the thick outer edge of the same, are the chief distinctive 
characters of this species. 
Locality —Near Veraghoor, in Trichinopoly district; the figured specimen is as 
yet unique. 
Formation.—Arrialoor group. 
XI. PLEUROTOMA, Lamarck, 1799. 
Pl. testa fusiformi, spira turrita; canali longo atque recto; columella levi; 
labro posterius sinu emarginato. 
We accept here the genus Plewrotoma in its restricted sense for the turreted 
shells with a long and straight canal and an emargination of the outer lip near 
the suture. The name Zwrris, substituted by Adams for Plewrotoma, has been very 
hastily introduced by American authors into paleontological literature, and with 
very little reason indeed. H. and A. Adams use (Joe. cit. I., p. 87.) Turris, Humph., 
instead of Plewrotoma, Lamk.; on p. 351 of the same volume they quote Twrris, 
Humph., not Bolten, as a synonym with Twrritelia, Lamk., and, on p. 246, they say, 
that they are indebted for valuable information to Dr. Gray, namely, that the 
Tvrrip#* belong possibly to the sub-order Toxtrera. If we consult Gray’s Guide 
of 1857 on this point, we find Adams’ Tvrerrm# replaced by the usual denomina- 
tion Prevroromums (p. 7) and under Turririp#, and Turris (whose ?) respectively 
some species treated, which the Adams refer to the Cancrrtarizp# and others. It 
appears that Dr. Gray has changed his mind since his communication with the 
authors of the “Genera.” Agassiz (in his Nomenclator) quotes the name Twrris, 
Humph. 1797, and does not know Bolten’s name. Chenu and Gabb add to Zurris 
the authority, Bolten 1798, and not Humphrey. 
* Vide Vol. Il, p. 614. H and A. Adams partly correct this misapprehension and call the family Torrzpm 
and the sub-family rurrry !! Has this change been introduced for the sake of avoiding a confusion with 
Turris and TvRRITID#& of Gray, or merely to correct the expressions in a grammatical point of view ? 
