UNIVALVES. 



PLATE XL 



Genus. ROSTELLARIA. 



Character. Shell spindle-shaped or sub-turreted, ending at the base in a canal 

 stretched out like a sharp beak; cheek joined to the spire; Zip whole or denticu- 

 lated, increasing by age ; a lacuna near the canal. 



Species. 



No. 1. Rostellaria rubicunda. Shell spiral, tuberculated, of a bright red 

 colour, invested with ridges near the beak, of a yellow colour; mouth yel- 

 low, and slightly striated. A native of Guinea. 



No. 2. Rostellaria serrata. Shell of a pale flesh colour, verging to a brown ; 

 upper end of the mouth terminating in a lacuna or trench, which reaches 

 almost to the top of the spire ; on the maxilla oris are eight spines, and 

 opposite to the first turn of the spire three spines, succeeded by three others, 

 after which a serrated process reaches nearly to the top. This most curious 

 shell is a native of the East Indies, and very rare. 



No. 3. Rostellaria sinuata. Shell of a pale brown ; and the maxilla oris 

 forming a waving line ; the mouth yellow, and the turns of the spire divided 

 by a channel. Native place unknown. 



No. 4. Rostellaria fissurella. Shell of a brown colour, with a high ridge, 

 lacunated, reaching nearly to the top of the spire. In its general form, 

 this shell bears a considerable analogy to the genus Scalaria. 



No. 5. Rostellaria ionica. Shell of a flesh colour, having about fifteen or six- 

 teen turns to its spire, nine of which are fluted at the upper part, and give 

 a considerable degree of elegance to the general form of the shell ; the beak 

 yellow, and very pointed ; the mouth, at the top, ending in a lacuna or 

 canal, is curiously ornamented by a ridge resembling the Ionic volute in 

 architecture. The denticuli or teeth of the mouth are mammillary, or 

 rounded, which adds to the singularity of its appearance and character. A 

 native of Amboyna, and very rare. Delineated from a specimen in the 

 Museum of Mr. Latham. 



No. 6. Rostellaria ala-draconis. Shell dark blue, tuberculated ; the mouth 

 yellow. This shell differs in form and colour from the Pes-pelicani, before 

 described. 



REMARKS. 



The genus Rostellaria has so near an affinity to the Linmean genus Strombus, as not to be 

 easily distinguished from it. The mouth, however, is considerably smaller, the spire different, 

 and, above all, there is not the furrow and usual excavation at the lower end of the maxilla 

 oris, which is always found in the Strombus, and with the beak bent back, which, in this 

 case, is nearly straight. There is also a considerable analogy in the cheek with the genus 

 Cerithium of Lamark, whose distinguishing characters will hereafter be more fully ex- 

 plained, with the reasons which have suggested some deviations from that celebrated and 

 ingenious Naturalist. 



