Mr. W. T. Blanford on Fairbankia bombayana. 399 belonged to the same Petaloproctus. Perhaps Rhodine Lovenij Malmgr., also belongs here. Malmgren follows the Maldaniea with the Ammocharidea as a distinct family, founded upon the genus Ammochares. He also describes a second genus, MyriocheUj which seems almost to coincide with PsammocolluSj Gr., but gives no cha-racter of the family, at least in his most recent work (^ An-nulata polychseta Spitzbergige ' &c.). Kinberg, who esta-blishes the same family, finds its character in the tentaculiform branchiae seated on the buccal segment, in a change of bristles, and in the presence of superior setae, and very numerous and minute uncmi placed below them. The author would indi-cate (at the same time bringing together Ammochares and Psammocollus) that the body consists of only a few segments, increasing considerably in length towards the middle, that these are all furnished with setse, and, with the exception of the foremost and hindmost, also with uncini (which, however, are placed in more than double and irregular rows, and not upon cushions), and that the buccal and terminal segments bear no plates, although the buccal segment may be produced in front into a lobe (cephalic lobe ?) slit up into branches at the anterior margin. Their similarity to the Maldaniea, already treated of, strikes one at once ; but with this concep-tion of the character, Kinberg' s genus Sandanis^ as to the position of which he seems to be still doubtful, cannot be added to them ; it should not be separated from Capitella. To Ammochares belong 4 species : — A. ottoms, Gr., A. assimiUsj Sars, A. tegula^ Kinb., and A, SundevalUj Kinb., the last known only by its anterior part. Of Psammocollus we know only one species, P. australisj Gr., from the island of St. Paul ; and of Myriochele likewise only one, Myriochele Heerij Malmgr., which has been ob-served, but not abundantly, at Spitzbergen and Greenland. XLIX. — Description of Fairbankia bombayana, a new Genus and Species o/" Rissoidse /ro??i Western India. By WiLLlAM T. Blanford, A.R.S.M., F.G.S., C.M.Z.S. The shell described below is one of the numerous peculiar estuarine forms so common on the shores of tropical seas. I have found but few specimens myself, and am indebted for a much larger number to the Rev. S. Fairbank and Dr. Leith. The latter very kindly procured me some living specimens about five years since. I had for a long time supposed the species to be a Rissoa ; but two years ago I had occasion to
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