| OCR Text |
Show 1867.] DR. J. E. GRAY ON CATILLUS. 999 the cavity of the ovate Catilli; while the compressed Limpets have the base arched ; that is to say, the side of the shell that embraces the cylindrical stem, or fits into the concavity in the roots of the large Fuci, is produced to fit the form of the body to which it is attached. The Limpets, when placed on a flat board, rock from end to end. The small thin shell of the small species that lives in Calcutta differs from the others in having the side of the cavity rather produced, like the Limpet above described. They are said to have been obtained in the Botanic Gardens and in the ditches near the city; but it is not stated if they live on stones, or if they live on the stems of the plants ; if the latter, that may explain the peculiarity of their form. The following species probably belong to this or the following genus ; but their opercula have not been observed or kept:- 1. NAVICELLA ENTRECASTEAUXII, Recluz, Rev. Zool. 1841, p. 380 ; Reeve, t. 8. f. 32. Hab. Australia, Point Entrecasteaux, King George's Harbour. 2. NAVICELLA ORIENTALIS, Reeve, Icon. t. 8. f. 33. Navicella ceerulescens, Reeve, Icon. t. 7. f. 29. Hab. India: Calcutta, in the Botanic Gardens (on plants?). 3. NAVICELLA EXIMIA, Reeve, Icon. t. 6. f. 26. Navicella reticulata, Reeve, Icon. t. 5. f. 20. Hab. Ceylon (F. Layard). Tribe III. ORTHOPOMINA. Operculum oblong, rather elongate; horny (true) operculum triangular, rather oblique as regards the axis of the horny plate ; shelly plate half oblong, rather narrowed above and rounded at the upper edge, with a verg slight fold diverging from the nucleus to the left upper margin ; the anterior cartilaginous flap large, broad (Figs. 4 a, 4 b). Fig. 4 a. Fig. 4 b. HP Fig. 4 a. O u ter surface. Fig. 4 b. Inner surface. ORTHOPOMA, n. g. Shell 1 This form is described from a single operculum which was found separated from the shells in the drawer of Navicella in Mr. Cuming's collection. I have no doubt it belongs to some shell in the collection, and most likely one named and figured by Mr. Reeve. Mr. Cuming, fortunately, in some instances attached an operculum |
