MORUM. 219 



Ex. G. rugosa, Linnaus, pi. 2-3, fig. 6. Opevculuiu, 

 G. echinophora, Linn(Bus, fig. 6, a, 6, h. Shell, G. echi- 

 nophoia, fig, 6, c. 



The form and structure of the operculum in this genus 

 is very peculiar; the shells are known by their transversely 

 ribbed and nodulous whorls, and their prominent, re- 

 curved, siphonal canal ; they are not numerous in species. 



Species of Galeodea. 



acuta, Gray. rugosa, Linn. 



Deshayesii, Duval. Tj'rrhena, Chem. 



echinophora, Linn. 



Genus MORUJM, Bolten. 



Shell ovately-triangular, tuberculated ; spire very short, 

 apex mucronate; aperture linear, anteriorly emarginate; 

 columella with papillary strioe ; outer lip reflected, inter- 

 nally plicated. 



Syn. Hystrix, Humph., not Linn. Ersina, Gray. 

 Larabidium, Link. Cassidea, g. Schum. Oniscia, Sotv. 

 Theliostoraa, Auct. 



Ex. M. oniscus, Linnmis, pi. 23, fig. 7. 



In the genus Morum the back of the shell is tuber- 

 culated, and the shell is covered with a fine, velvety epi- 

 dermis. There are about nine species known. 



Species of Morum. 



Lamarckii, Desh. tuberculosum. Sow. 



oniscus, Linn. xanthostoma, A. Adams. 



