Purpura Persica. P. Rudolphi. P. patula. P. collumellaris. P. succincta. P. consul. P. armigera. P. bitubercularis. P. hippocastanum. P. undata. P. hæmastoma. P. manicella. P. bufo. P. callosa. P. neritoides. P. planospira. P. callifera. P. coronata. P. sacellum. P. squamosa. P. rugosa. P. textilosa. P. sertum. P. Francolinus. P. limbosa. P. ligata. P. cruentata. P. lapillus. P. imbricata. P. lagenaria. P. cateracta. P. bicostalis. P. plicata. P. fiscella. P. thiarella. P. rustica. P. carinifera. P. scalariformis. P. hystrix. P. deltoidea. P. unifascialis. P. retusa. P. trochlea. P. semi-imbricata. P. echinulata. P. clavus. P. fasciolaris. P. vexillum. P. bizonalis. P. nucleus. _P. Persica._ The Persian Purpura. Pl. 28, fig. 4. Transversely sulcated and striated between the ridges; colour burnt-umber, ridges yellowish, with dark brown spots; upper ridge and the superior edges of the volutions mucronate; interior sulcated and striated. _P. lapillus._ The common Purpura. Species small, white, sometimes banded with yellow or brown, with a scaly surface. 5. Monoceros. The Unicorn. Five species. Derived its name from the long, conical-pointed, somewhat recurved tooth in the outer lip, by which alone it can well be distinguished from the Purpura; and with this characteristic difference the description of the shell of the Purpura will answer for this genus. Monoceros cingulatum. M. imbricatum. M. striatum. M. glabratum. M. crassilabrum. _M. cingulatum._ The belted Monoceras.