382 MAZATLAtf UNIVALVES 



This fine and graceful species appears to replace S. gigas on 

 the W. coast of N. America, as S. Peruvianus does on the 

 Pacific shores of S. America. When very young, the spire is 

 fusiform, with spiral striae and transverse folds as in Fusidse 

 (Colidse, Grray^) Gradually tLe whirls lose their sculpture, 

 and envelop each other, with a broad channel below the suture 

 and an obtuse angle near the periphery. Beneath this are 

 developed more or less faint obtuse spiral ribs, ending in slight 

 crenations of the but-moderately expanded outer lip. Pos- 

 terior channel narrow, ascending the spire. Epidermis de- 

 ciduous, nearly smooth. Menke has described the operculum 

 as like that of S. gigas, lancet-shaped, slantingly elliptical, 

 with a keel-shaped line near the middle. It is figured in 

 H. $ A. Ad. Gen. i. pi. 27, f. la, Ib. The entire stock of this 

 beautiful shell in the L'pool Col. shared the fate of the Spondyli 

 and large limpets. The specimens here displayed are from the 

 Havre Col. Long. 8 '5, long. spir. 1'2, lot. 6 '3, div. 90. 



Hob. Gulf of Nicoya, on reefs at low water, Cuming=T&boga, 

 (fragments) C. S. Adams. S. W. Mexico, P. P. C. 

 Mazatlan , not uncommon ; L'pool fy Havre Coll. . 



Tablet 1821 contains a young specimen, in perfect condition, 

 6*5 in length. 1822, a fine adult specimen. 



448. STEOMSUS GEANULATUS, Swains. 



Bligh Cat. App. p. 8. Wood Ind. Test. Suppl. pi. 4, f. 21. 

 Swains, in Hani. Exot. Conch, p. 36. Sow. Thes. Conch. 

 p. 33, no. 39, pi. 9, f. IW.Kien. Icon. Conch, p. 28, pi. 22, 

 f. 1. Lam. An. s. Vert. vol. ix. p. 713, no. 37. Duel, in 

 Chen. III. Conch, pi. 11, f. 5. 6. Kust. Conch. Cab. p. 64, 

 pi. 13, f. 13. Rve. Conch. Ic. pi. 14, f. 32. C. . Ad. Pan. 

 Shells, p. 113, no. 124. Wee. in Zeit. /. Mai. 1851, p. 21, 

 no. 93. 



This well-known species appears to abound in the warmer 

 latitudes, but not to flourish at Mazatlan. It is easily recog- 

 nized by its elevated spire, very stout nodules, and variegated 

 painting. Epidermis rather rough, adherent. Long. 3'44, 

 long. spir. '96, lat. T64, div. 50. 



Hob. St. Elena and G-alapagos ; sandy mud, 6-8 fm. ; Cuming. 

 Panama, Col. Jewett. Taboga, 7 dead sp. C. B. Adams. 



