OF SOUTHERN INDIA. 237 
The family will be found most probably represented already in the paleeozoic 
formations, from which Serpuloid shells are numerously reported. From the Trias 
several species of Vzrunrrps are well known, and they gradually increase in number 
through the successive formations. When speaking of the fossil forms, it must 
also be taken into consideration, that their imperfectness on one hand, and the 
uniformity in structure with others, very often prevent the exact determination of 
the species: The uncertainity of distinction between a Gastropod and an Annelid 
diminishes also the interest, which would be otherwise paid to them. 
We give here a short review of the characters of those genera, which are 
represented in cretaceous rocks, appending a few notes upon the others, as to 
their value in the conchology of fossil remains. 
1. Tubulostiwm, Stoliczka, 1868. 
Testa libera, solida sublevigata, planorboidea seu late conica, sepissiime 
sinistrorse-, rare dextrorse-torta ; anfractibus interne tubulosis, externe callositate 
junctis, in superficie rotundatis seu carinatis ; apertura valde atque abrupte contracta, 
tubulosa, rostriforme prolongata. 
The principal characteristic, upon which this genus is proposed, consists in 
the narrow and tube-like prolonged aperture. The form of the shells varies from 
planorboid to broadly conical. The embryonal whorls are distinctly spirally coiled, 
but not any of the very numerous specimens of the two species give a decided 
proof, that they have been attached to any foreign object. These embryonic whorls 
are, however, often worn of. In advanced age the shells were evidently quite free, 
and thus it is not unlikely, that they had a somewhat more developed foot, than 
other attached Vzrunrrm.s, and approached, in this respect, the family Caczpz. 
The internal space of the whorls is tubular, but externally the callosity is gener- 
ally largely developed. In a microscopical section the shell distinctly shows three 
layers, of which the middle one is somewhat thicker, than the internal or external one. 
These two thinner layers appear to be composed of a rather consistent [milky white | 
substance, while the central one seems to present some kind of transverse 
striation, as if indicating the succeeding layers of growth, though these distinctions 
are not sufficiently clear to be observed. The outer or callous mass is quite homoge- 
nous. The Gastropodous character of these shells is pronounced, as already stated, in 
the spiral nuclear whorls and the three layers of which they are formed. The callosity 
has also more probably been deposited from the mantle of a Gastropod than from 
an Annelid. We are not acquainted with any living species, which possesses a 
similar tubular aperture, to that known in the fossil forms. Of these the Serpule, 
like S. spirulea, Lamarck, will probably have to be placed in this genus, although 
I am for the present unable to compare good specimens of this species with our 
originals. The jurassic Verm. twmidus, Sow., is certainly a Tubulostium. The 
Spirorbis leptostoma, Gabb (Journ. Ac. Phil., 2nd Ser., Vol. IV, p. 385, pl. 67, 
fig. 36 (not 41), from the American tertiaries, would seem to belong also to this 
genus; and several others may be found subsequently. The two new species from 
South India are 7. discoideum and T. callosum. 
3.N 
