OF SOUTHERN INDIA. 219 
Very young specimens have the whorls quite flat, anteriorly always keeled and 
gradually tapering towards the posterior suture. In older and more grown speci- 
mens (Pl. XVI, Fig. 14) the whorls become somewhat concave about the middle, 
but they are on both the sutures much contracted. Among the numerous fine spiral 
striz there are generally three or four, which increase in strength with the age and 
size of the specimen. 
Locality.—Near Arrialoor, in whitish sandstone. 
Formation.—Arrialoor group. 
5. TURRITELLA (ToRCULA) AFFINIS, Willer, Pl. XVII, Bigs sb 7-18)- Pls xox, 
Figs. 12-13. 
1851. Turritella affinis, Miller (Pet. Aach. Kreide. II, p. 31, Pl. IV, Fig. 11). 
Turr. testa conica, anfractibus ad margines crasse sed obtuse carinatis, ad medium 
excavatis, in superficie numerose striatis: striis incrementi minutissimis, insinuatis ; 
basi ultimi anfractus subconvexa, paululum prominente ; apertura rotundate quadran- 
gulari, ad marginem exteriorem emarginata. 
Spiral angle 22°; sutural angle 7°- 8°. 
Height of last whorl : total of shell (considered as 1:00) 
Height of penultimate whorl : height of spire (consd. as 1:00) ... aco. WES 
33 a » + its width (consd. as 1:00) a eno Ls 
Each of the whorls is ornamented with three keels, of which the middle one 
is the thinnest, and placed somewhat below the centre. The anterior keel is gener- 
ally sharper and often stronger, while the posterior slopes gradually towards the 
suture. The entire surface of the shell is ornamented with fine spiral striz of 
different strength, but according to the state of preservation and other causes the 
appearance of the shell is very much changed. Sometimes the surface of the shell 
seems to be almost smooth ; in other specimens there are only a few strize traceable 
above and below each keel, varying in strength among themselves; again, in others 
there are tolerably strong striz present, one bounding each of the two stronger 
keels above and below, and there are besides one or two similar striz along the 
posterior and one along the anterior suture. 
In young specimens the fine striation almost disappears, and the difference in 
the strength of the upper and lower and the median keels is not sc apparent. The 
strize of growth produce on the finer spiral ornamentation often a slight granu- 
lation. , 
As I have already observed, our specimens agree in every respect with the 
figure and description of the species from the cretaceous deposits of Aachen, but 
there are a number of other species known, which are very closely related, and 
several of them perhaps identical with the above named species. I would specially 
mention 7. Omalusi, Miiller, (ibid. fig. 12); 7. nitidula, Binkhorst (Monog. Gast. 
et Ceph. Maestricht, p. 32, pl. 5°, fig. 12), and 7. Hichwaldiana, Goldf. (Pet. Germ. 
III, pl. 197, fig. 4). The figure of this last species, given by Zekeli in the 
