COLUMBELLA. Panama Sheik. 81 



Purpura undata Eeeve Conch. Icon. pi. 9. f. 43. Sept. 1847. 



hcetnastoma Menke (non Lam.) Zeitschr. Malak. 



p. 182. Nov. 1847. 



undata Mrs. Gray, Moll. pi. 87. a. f. 1. 1850. 



Station. — Under stones at low water ; Cuming I Eeeve. 

 We found this species under stones near tlie low water 

 mark of the neap tides. 



Hahitat. — Unknown ; Lamarck. 



Acapulco ; Humboldt and Bonpland ! Valen- 

 ciennes. 

 South Sea and Shores of St. Helena ; Kiener. 

 Monte Christi ; Cuming I Eeeve. 

 Monte Christi ; Jay. 

 Panama ; C. B. A. I 



We collected 180 specimens on the reef at Panama. — This 

 species and P. luBmasloma are sometimes confounded. The 

 latter inhabits only the Mediterranean and the eastern shores 

 of the Atlantic, in warm latitudes. It is, therefore, extremely 

 probable that Dr. Menke's P. hoRTnastoma from Mazatlan is the 

 true P. undata. As Kiener confounds three distinct species, 

 there can be no advantage in learning whether his "Sainte 

 H61^ne " is St Helena in the Atlantic, or St. Elena in West 

 Columbia. 



COLiTJMBEIiIiA. Numerous species of this genus, and 

 an incredible multitude of individuals were found at Panama. 

 Many of the species are among the most beautiful in the genus. 

 Perhaps no other fauna equals the marine Pacific fauna of tro- 

 pical America for its development of this genus in these three 

 characters — number of typical forms, number of individuals, 

 and their size and elegance. The number of species which 

 have been collected at Panama much exceeds the number in 

 the entire genus which were known to Lamarck. While very- 

 few of the species which we collected have been described in 

 21 



