OF SOUTHERN INDIA. 261 
7. Couthouyia, A. Adams, 1860, (Ann. Mag. Nat. Hist., V, p. 410), is another 
similar form, founded also upon a Japanese shell. A. Adams (loc. cit., p. 410,) 
says, that the three last named genera, and some others belonging to this sub- 
family, ought to be united in a distinet family under the name of Fossaripx. 
The Natica carinata, Sow., (Trans. Geol. Soc., Lond., IV, 1836, p. 241, 
pl. 18, fig. 8), may belong to the rossarzvz, because it has a thick shell and 
strong spiral ribs, like many species of this sub-family. We do not know any 
other cretaceous species, than the doubtful Fossar? Nebrascensis, Meek and 
Hayden, quoted in Proc. Acad., Phil., 1860, p. 423. 
b.  Sub-family,—LACUNINA. 
Shells solid, depressed, conical or globular, last whorl ventricose, much larger than 
the previous ones; aperture occasionally effuse (more so in fossil species) ; imner 
lip flattened and expanded at the termination of the columella, which is fissured 
or umbilicated ; surface often smooth, occasionally ornamented with spiral strie, or 
transverse tuberculations. 
Gray places Lacuna in a separate family, but there does not seem to be 
sufficient reason for doing so. The only distinction from the animals of the other 
Littorine is the usual want of horny jaws and the presence of two small posterior 
appendages on the operculigerous lobe in Lacuna. Still these and the above- 
mentioned characters, that is, the ventricose or globular form of the shells, the 
existence of a fissured or hollow columella, the general smoothness of the sur- 
face and the flattened inner lip, would seem to make the distinction of a sub- 
family very desirable, without losing the idea of unity with other allied types 
of shells. 
The principal genera included in this sub-family are the following :— 
1. Modulus, Gray, 1840, including very characteristic globular or depressed 
forms, the columella terminating anteriorly with a strongly produced tooth and 
the margin of the aperture having anteriorly a shallow insinuation at the base. 
2. Lacuna, Morton, 1827. A very large number of fossil species of this 
genus have been lately described by Deshayes from the Paris basin, and many of 
the forms show a very close relation to Littorina, differing, however, by their want 
of ornamentation. The classification of Cythina ( ? Conrad) is doubtful. 
3. Lnthoglyphus, Muhlfeld, 1821, (H. and A. Adams’ Gen. I, p. 820). This 
genus is in some respects the fluviatile representative of Lacuna and Littorina. 
The form of the shell makes it very much allied to these two genera, and distin- 
guishes it from similar forms of the Rzssorpz. Frauenfeld in his Monograph of 
Lithoglyphus (Verhandl. zool., bot. Gesellsch., Wien, 1863, Vol. XIII, p. 193, &c., 
and 1865, Vol. XV, p. 529, &c.), pronounces the expanded form of the inner lip, 
covering the hollow columella, as an important character of the genus, and it is 
principally on this account, that we would prefer to place Lithoglyphus rather in 
the zacunz#, than in the zrrrorryiyz. Frauenfeld describes, in the above quoted 
papers, twenty recent species. 
3T 
