MAZATLAN UNIVALVES 381 



Kiener thinks that to C. brevis should be united C. rigida 

 and C. goniostoma ; and certainly the species have a strong 

 resemblance, as has also C. bicolor, Hinds. The Mazatlan 

 shells, of which some hundreds have been examined, vary in 

 the elevation of spire, in colour, sculpture, and in the angle of 

 the aperture. Sometimes the labium is parallel to the axis, 

 sometimes at an angle of nearly 30". Sometimes the ribs are 

 sharp, distant, and scarcely nodulous ; sometimes running into 

 each other, with strong tubercles. Sometimes the shell is near- 

 ly white, sometimes of a rich purple brown, or brown orange. 

 The first two whirls are smooth, followed by one which is 

 finely cancellated, not shouldered. The umbilicus varies in 

 size, and is more or less sculptured. The largest specimen 

 measures long. 1*04, long. spir. '54, lat. '78. div. 80. 



A slender sp. 1'04, '6, '75, 70. 



A broad sp. '8, '37, ,. '64, 90. 



Hob. Conchagua, San Salvador ; on sandy bottom, 8 fm. ; 

 Cuming. Taboga ; 1 sp. C. J5. Adams. Mazatlan ; not 

 uncommon ; Upool Col. 



Tablet 1814 contains 3 young sp. 1815, 3 sp. ordinary broad 

 growth. 1816, 2 sp. acuminated. 1817, the largest sp. with 

 the aperture only touching the penultimate whirl at the basal 

 keel. 1818, 3 sp. shewing variations in colour. 1819, 2 sp. 

 ribs distant. 1820, 2 do. close. 



FAMILY STEOMBIDJE. 

 GENUS STKOMBUS, Linn. 



J- 447. STEOMBUS G-ALEATUS, Swains. 



Phil. Mag. fy Journ. 1823, p. ^IGray Descr. Cat. p. 2, 



no. 2. Sow. Thes. Conch, p. 36, no. 54, pi. 10, f. llk.Kien. 



Conch. Ic. p. 5, pi. 2 Lam. An. s. Vert. vol. ix. p. 710, 



no. 3&.I>ucl in Chen. III. Conch, pi. 26, 27, f. 1. Kust. 



Conch. Cab. p. 13, no 5, pi. 4 a, f. 1, pi. 46, f. 1, 2. Eve. 



Conch. Ic. pi. 3, sp. 3, f. 3. Mke. in Zeit.f. Mai. 1851, p. 20, 



no. 92. 

 Strombus galea, Wood, Ind. Test. Suppl 1828, p. 14. pi. 4, 



f. 13, 14.- C. B. Ad. Pan. Shells, p. Ill, no. 122. 

 Strombus crenatus, Sow. Tank. Cat. 1825, App. p. xix. 



