OF SOUTHERN INDIA. 147 
determination is not very certain. It is found with voramrpivs certain species of 
Narrer and others, in at least partially brackish deposits, and it would not be very 
difficult to associate it with the wzzavopsrnm. Gabb (Proc. Acad. Nat. Se. Phil. 
1860, p. 94, Pl. 2, Fig. 11), describes a P. dubia, but this is indeed more than 
doubtful, and judging from the figure, it can belong quite as well to any other even 
approximately allied genus. 
Pictet (Mat. Pal. Suisse, 3me. Ser., p. 673), mentions from the Gault of Cosne 
an undescribed species which, he thinks, may belong to the Purruri.s, but whether 
to this or the next sub-family is not yet known. 
It is possible that the Voluta corrugata, Binkh. (Monog. Gast. et. Céph. craie 
de Limbg., 1861, p. 14, Pl. V, Fig. 1), is a Purpura, if no columellar plaits exist. 
Buvignier (Statist. d. 1. Meuse) describes some jurassic Purpure ; but these 
had better be referred provisionally to Purpuroidea, until the relations of this genus 
to Stramontia and Thalessa, two forms of shells, quoted as sub-genera of Purpura, 
are satisfactorily settled. It would appear that all three ought to form one genus, 
apart from Purpura proper. 
b. Sub-family--RAPANIN ZA. 
The shells of this sub-family are distinguished by a comparatively very short 
spire, rapid increase and ventricose form of the last whorl, being anteriorly produced 
into a shorter or longer, but always distinct canal. The inner lip is always strongly 
developed, often thickened, toothed posteriorly or wrinkled in front; the umbilicus 
remains usually uncovered, at least partially. 
The genera which appear to be admissible in this group are as follow :—~ 
Cuma, Humphrey, 1797. 
Litiaxis, Swainson, 1840. 
Rapana, Schumacher, 1817. 
Rhizochilus, Steenstrup, 1850. 
Vitularia, Swainson, 1840. 
Morea, Conrad, 1860. 
Rapa, Klein, 1753. 
Tudicla, Bolten, 1798. 
Whitneya, Gabb, 1864, Calif. Paleont. I, p. 103; reminds one 
more of Melapium, H. and A. Adams (Genera, I, p. 186). 
’ 10. Chorus, Gray, 1847. 
For the secondary deposits this sub-family is by much more important than 
the previous. Scarcely any jurassic species are known with certainty, but the 
number of cretaceous is comparatively large. Most of them have been described 
under Pyrula, and Keferstein (m Bronn’s Klassen und Ordnungen des Thier- 
reiches, III, p. 1047) and others class in fact Rapa, Rapana, &c. with Pyrula, 
Lamarck, without acknowledging even a generic distinction. There is, however, 
not very much doubt now, that Lamarck’s genus Pyrula cannot be retained, 
even when Ficula or Sycotypus have been separated, as proposed by Deshayes 
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