224 MAZATIAN UNIVALVES 



plaited spiral frill, prickly inside. Between this and the outer 

 margin are 4 — 6 (generality 5) fine emerald necklaces, supported 

 on slender spiral ribs, witli deeply channeled interspaces. The 

 margin and the body of the operculum are white. The oper- 

 culum of its neighbour, C. saxosum (Panama, C. B. Adams, 

 S. "W. Mexico, P. P. C.) is formed on a much coarser plan, 

 with the central callus not covering the .umbilicus, the frill 

 rather granular than plaited, the three rows of necklaces close 

 together, without deep channels, and -with large gi-anules on 

 the margin. All the jMazatlan shells were of the tj-pical form, 

 with the spire elevated, whirls well roimded, with distant rows 

 of nodules. Whether the C. f. depressum is a variety of this 

 form, (as I described it in the P. Z. S., copying E-eeve's error 

 in the name, and not aware that Kiener had figured it,*) 

 or another species, cannot be decided without a knowledge 

 of the operculum. The shell is distinguished from all varieties 

 of C. saxosum. by the non-corrugation of its surface. Long. 2 '56, 

 Zai'. 2-5, f?/i'. 90'. 

 Hah. — Punta St. Elena, Cuming. — jMazatlan ; abundant; 



Upool Col. — San Diego, Lieut. G-reen. — Sitka, Wosnessenski, 



Middendorfi". 



Tablet lOSl contains the largest specimen, in its natural 

 rough state. — 1082, the sp. which suffered least from hot acid. — 

 1083, 6 opercula of different ages, and of exquisite beauty. 



Genus PHASIANELLA, Lam. 



Lam. Phil. Zool. 1809.— Pliil. Haiidh. Conch, p. 205. 

 Eutropia, (Humph. J Grcii/, 1847. — JI. ^ A. Ad. Gen. vol. i. 



p. 389. 

 Phasianus, Monlf. 1810. — Tricolia, Itisso, 1826. 



283. Phasianella perforata, FMl. 



Zeit. f. Mai. 1848, p. l&i, no. ZL—Kust. Mart. p. 20, sp. 24, 



pi. 4, f. 14. 

 Comp. Pha^ianella tessellata, Bech, 1838, Pot. ct. Mich. Gall. 



vol. i. p. 312, pi. 29, f. 7, 8.—C. B. Ad. Contr. Conch. 1850, 



p. 67.— Phil, in Kxst. Mart. p. 18, sp. 22, pi. 4, f. 12.— = Ph. 



minuta, Anton, 1839, Verz. p. 60, no. 2129, (non Sow.)—='Ph. 



* I have seien no letter-press in explanation of the figure, nor are any dates 

 given in Kiener's monogruphs, by which questions of priority can be determined. 



