r«EUDOLlVA. 131 



Syn. ]\[ouoceros, Lam., not Block. Unicornus, Montf. 

 Rudolphus, CJtem. Riidolpha, Schum. 



Ex. A. striata, Lamarck, pi. 13, fig. 7. Operculum, 

 A. unicornis, Brugiiiere, fig. 7, a, 7, h. Shell, A. calcar, 

 Martijn, fig. 7, c. 



The species of Acanthina are most numerous on the 

 South American coasts of the Pacific Ocean ; the genus 

 differs from Purpura in having a tooth-like spine on the 

 outer lip. 



Species of Acanthina. 



acuminata, Sow. punctata, Gratj. 



calcar, Martyn. spirata, Blainv. 



coruigera, Blainv. striata, Latn. 



cymatium, Soland. truucata, Reeve. 



glabrata, Lam. tuberculata, Gray. 



grandis. Gray. unicornis, Briiy. 

 maculata, Gray. 



Genus PSEUDOLIVA, Swainson. 



Shell ovate, solid, subglobose ; spire very short, suture 

 slightly channelled, whorls tumid round the upper part ; 

 aperture oval ; canal very short ; inner lip arcuated, with 

 a callosity at the hind part ; outer lip thin, furnished at 

 the fore part with a small tooth or callosity. 



Syn. Gastridium, Soiv., not Modeer. Gastridia, Gray. 

 Pseudodactylus, Herm. 



Ex. P. laevis. Martini, pi. 13, fig. 8. Operculum, 

 P. laevis, fig. 8, a, 8, h. 



PseudoUva, known only by its shell and operculum, 

 reminds one of Olivancillaria among the Dactylida;, 

 but is distinguished by its large purpura-like operculum. 



