Notes on caenozoic and recent mollusca from the Dutch East Indies 4—5 (Naticidae)

The palaeontologist is always glad, when to the generally scanty remains of former faunas, which are his only hold when he has to reconstruct an image of life in former epochs, something unexpected and new is added, even when the new find only confirms his opinion about life in the period from which it derives. So I was very glad to find a number of corpuscles which I believe to be fossil faecal pellets, in a shell of Natica cf. helvacea Lamarck deriving from pleistocene beds in East Java, although I had never doubted of the normal digestion of Prosobranchs which lived so many centuries ago, ending in the production of faecal pellets just as we know to be produced by Prosobranchs actually. The shell (fig. 1a) was found in the lowest of three fossiliferous horizons in the lower pleistocene Poetjangan layers NW. of Modjokerto (Residence of Soerabaja, Java)2). As to its identification, I think it is too young to be quite sure about the species, because it is difficult to separate juvenile Natica helvacea Lamarck from young N. vitellus Linné. The shell was filled by the hard, fine grained matrix and when removing this cast (fig. 1b), I found the fossilised faecal pellets (fig. 1c), which were situated at a distance of about ¼ to ½ of the last whorl from the aperture. They were about 90 in number; several of them were clustered together in parcels of 3 or 4 in a characteristic way. The pellets themselves have a cylindrical shape with rounded ends; frequently one end is slightly more pointed than the other. Their length is scrarcely more than 1 mm., the diameter slightly under 0,5 mm.