Cassidaria echinophora. C. Tyrrhena. C. cingulata. C. striata. C. oniscus. _C. echinophora._ The tuberculated Cassidaria. Pl. 27, fig. 5. Species oval, sub-globular, canal sub-ascendant, with tuberculated belts or ribs. _C. Tyrrhena._ The Tyrrhenian Cassidaria. Species ovate, grooved transversely, volutions convex; apex with one tubercle; tawny colour. 2. Cassis. The Helmet Shell. Twenty-five species. This genus was formed from the Buccinum, from which it is easily distinguished; the latter having only a notch at the base, and the Cassis with a canal abruptly turned towards the back of the shell. Shell inflated oval, sub-involute, spire very little projecting; aperture long, oval, sometimes very narrow, terminated anteriorly by a very short canal, sloped and recurved obliquely towards the back; the right edge more or less concave, reflected backward, and often dentated within; the columella covered with a large callosity, denticulated or wrinkled in all its length; operculum horny. Cassis cornuta. C. tuberosa. C. Madagascariensis. C. flammea. C. fascinata. C. glauca. C. rufa. C. pennata. C. testiculus. C. achatina. C. crumena. C. plicaria. C. areola. C. zebra. C. decussata. C. abbreviata. C. sulcosa. C. granulosa. C. saburon. C. canaliculata. C. pyrum. C. Ceylanica. C. semigranosa. C. vibex. C. erinaceus. _C. tuberosa._ The tuberous Cassis. Pl. 28, fig. 5. Species in which the aperture is long, the external edge almost straight, and the spire with thickened bands. _C. flammea._ The flaming Cassis. Species in which the aperture is sub-oval, and the external edge excavated; spire short, base triangular; columella rugose; outer lip thickened. _C. areola._ The draught-board Cassis. Smooth, shiny, white, with square orange tesselated spots; spire short and conical, with decussated striæ; lower part of columella rugose. 3. Ricinula. Nine species.