Neritina (Clithon) subocellata, v. Martens, MS

With the species of the Genus . Neritina, which I received for revision from the Leyden Museum of natural history , I found three specimens of this form, which Prof, von Martens, after specimens in my own collection , thought to be new and named it subocellata; but as far as I know it has not yet been described. With the approbation of the Conservator of the conchological department of the Museum I will now give a description. Shell nearly globular, delicately striated in the line of growth, with a few striae in the form of folds near the suture, and with microscopic spiral striae. The colour is greyish olive-green, with small blackish spots, which are rounded or triangular, sometimes flow together and vary greatly in size and number; they are mostly bordered by a very small rim of a lighter colour. The last whorl is more or less angular above and shows there from one to four spines in some examples, others are entirely spineless, but show still traces of them on the penultimate whorl and one is quite destitute of spines. The spines are short, curved upwards and sometimes a little backwards. Spire very small, eroded, probably 2 whorls and a half, which form a flat cone. Suture not deep, covered by the margin of the next volution. Aperture moderate, obliquely semi-elliptical; upper margin curved, outer and lower margin rounded, interior of the aperture bluish, the callosity near the muscular scar, moderately long, low; the columellar plain callous above, with a narrow layer of enamel, which has the aspect of shagreen, becomes thicker towards the free edge and shows there a small sinuosity with 4 to 6 denticles, besides a few secondary ones; the sinuosity is bordered above by a much greater dentition and still higher are a few crenulations. which form grooves to behind.