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Show 1867.] DR. J. E. GRAY ON CATILLUS. 993 belly, inner side and front and back part of the limbs, and the side and under surface of the tail yellow. Hab. Eastern Peru, near Xeberos (E. Bartlett; Brit. Mus.). The black part of the hands and legs near the yellow colour is varied with more or less abundant yellow hairs." I have named this fine species after Mr. A. D. Bartlett, the Superintendent of the Society's Gardens, and his son Edward (who discovered it). 8. Notes on Catillus, Humphrey, or Navicella, Lamarck, with Descriptions of T w o N e w Genera. By Dr. J. E. G R A Y , F.R.S., V.P.Z.S., F.L.S., &c. Linnaeus and Bory St. Vincent referred this shell to the genus Patella. Chemnitz properly removed it to Nerita; and De Roissy considered it a species of Crepidula of Lamarck. Other authors have regarded it as the type of a genus. Thus Humphrey called it Catillus, Schumacher Sandalium, Ferussac Septaria, and Lamarck Navicella. Lamarck and Ferussac divided their shells into two or three species :-the one having an oval, convex, more or less thick, solid shell, and more or less acute spire, which was called N. elliptica, Lamk., and Septaria borbonica, Ferussac ; the other a narrow oblong thin shell, more or less rounded at each end, called N. lineata, Lamk., and Septaria navicula, Ferussac. These two species are the types of two forms, each of which has been divided into several species. The forms are generally distinctly marked ; but there are a few specimens which seem to be more or less completely intermediate between them. Mr. Lovell Reeve, in his ' Conchologica Iconica,' has divided the specimens into thirty-three species, or pseudo-species (most, if not all, of them figured from specimens in Mr. Cuming's collection), separated from each other by slight modifications in the form of the shell and of the inner lip, and in the distinctness and distribution of the colours. I think I may state, without any fear of contradiction, that it is utterly impossible to distinguish a large proportion of the species proposed in'this work by the specific characters, or even by the figures given. Such characters and figures are merely to satisfy the rule that a species is not established unless it is characterized ; but surely that implies that it shall be characterized so that it may be distinguished ; otherwise, as in this case, it is a mere pretence, and therefore best avoided. Mr. Reeve does not give figures of or describe the operculum of any of the species, which is the less excusable as Mr. Cuming's collection, from which the figures are taken, contains the opercula of more than a third of the shells which he has regarded as species ; and the opercula of the different specimens present such modifica- |
