1862,] DE KONINCK INDIAN FOSSILS. 7 



other, although it is easy to recognize at first sight that they belong 

 to the same species. In all of them the upper valve is conical ; but 

 in the first two (figs. 7 <fc 8) this cone is truncated, while in the 

 third the summit is slightly inclined on one side, and recalls the shape 

 of certain species of Pileopsis (fig. 9). The shell is very brilliant, and 

 has all the appearance of that of a recent species. Its surface is 

 covered with a great number of irregular striae and wrinkles, pro- 

 duced by the successive growth of the shell. These wrinkles serve 

 here and there as a basis for little tubes, similar to those which rise 

 from certain Producti. The distribution of these tubes is rather 

 irregular, as one may perceive by a glance at the figures. The test 

 is laminated and extremely thin. 



I have been able to examine the lower valve in a single specimen 

 only ; it is circular in form, entirely smooth, and feebly grooved in 

 the middle. This character probably depends on the shape of the 

 object to which the shell has been attached towards its centre. Four 

 small, circular tubes (fig. 7 b) may be perceived, of a rather darker 

 colour than the rest of the shell ; they appeared to me to have been 

 the bases of small internal tubercles. 



The diameters vary too much to be indicated here ; they can be 

 easily taken from the figures, which have been drawn with the 

 greatest care. 



16. Pecten Flemingianus, DeKon.. PI. IV. fig. 4. 



This species is of medium size, longer than wide, and suboval in 

 shape. Its surface is ornamented with a small number (8-9) of 

 slightly marked, radiating ribs ; the space between the ribs is almost 

 entirely smooth. Nothing can be seen on it besides some lines of 

 growth, which are hardly perceptible to the naked eye. The ears 

 are small, triangular in shape, and their surface is smooth. 



The length of the only known specimen is 16 millimetres, and the 

 width 14 millimetres. 



17. Pecten Asiatictjs, De Kon. PL IV. fig. 6. 



This species, which is much larger than the following, is a little 

 wider than long, and slightly, but rather regularly convex. Its surface 

 is ornamented with twelve or fifteen radiating ribs, especially apparent 

 towards the middle of their length, but partially disappearing towards 

 the margin. In each furrow formed by these ribs there are from three 

 to five much thinner ribs, less regular than the principal ones, and 

 also more marked in the lower and central parts of the valves. 

 The lines of growth are hardly visible even by the help of a hand- 

 magnifier. The ears are small and rectangular, and are covered with 

 small striae parallel with the cardinal edge. The beak is tolerably 

 prominent. This species possesses at first sight some analogy with 

 the P. plicatus, Phill. ; but, upon careful examination, it is easily 

 distinguishable by its small ribs, which are totally absent in the latter 

 species. 



The length is 4 centimetres, and the width 4| centimetres. 



