376 MAZATLAN UNITALYES 



the top and bottom of the back. The pustules are almost 

 always of a rich reddish orange, with a ring of dark at the 

 base. The dorsal line is scarcely indented, but is free from 

 pustules. The front ribs are often continued faintly over the 

 sides. Shape oval or produced, with beaks more or less 

 prominent. Labral teeth about 18 ; sometimes these are 

 formed by principal ribs ; sometimes by fainter intercalary 

 ones, as in T. Solandri ; sometimes there are marginal inter- 

 calations. Pustules very variable in number ; two dwarf 

 specimens have 94 and 176 respectively. ColumeMar excava- 

 tion long and deep, bounded externally by a sharp rib. The 

 smallest adult specimen measures long. "51, lat. '3, alt. '21. 



The largest do. ' "94, "6, "4. 



A broad sp. '78, '56, '36. 



An elongated sp. ,, "76, *4, "34. 



Hob. Mexico, Humboldt fy Bonpland. Panama and Isl. 



Plata, [near Cape San Lorenzo, lat. 1'6] under large 



stones, at extreme low water mark of spring tides only, rare ; 



C. B. Adams S. W. Mexico, P. P. C. Mazatlan ; L'pool 



Col 



Tablet 1781 contains 7 sp. in different stages of growth. 

 1782, 7 sp. white conspicuous. 1783, 7 sp. pustules few, large. 

 1784, 7 sp. usual state. 1785, 7 sp. pustules small, crowded. 

 1786, 3 sp. broad form. 1787, 3 do. elongated form 1788, 

 2 sp. ashy tint, pustules scarcely bordered. 1789, 2 sp. shew- 

 ing extremes of size. 1790, 2 dwarf sp. shewing extremes of 

 shape and markings. 



I 440. TRIVIA BADIANS, Lam. 



Cyprsea radians, Lam. Ann. Mus. vol. xvi. p. 102, no. 62 : 

 *An. s. Vert. vol. x. p. 540, no. 62 Gray Zool. Journ. vol. iii. 



p. 364. Vol. in Numb. Eec. Obs. vol. ii. p. 335. Pot. Sf 



Mich. Moll. Mus. Douai, vol. i. p. 485. Sow. Condi. III. 



pi. 119, f. 146. Eve. Conch. Syst. pL 286, f. 146 :- Conch. Ic. 



pi. , f. 117. Kien. Icon. Conch, p. 129, pi. 23, f. 3. C. J?. 



Ad. Pan. Shells, p. 37, no. 10. 

 Cyprsea oniscus, Wood Ind. Test. pi. 17, f. 58, (err. typ.) Non 



C. oniscus, Lam. An. s. Vert. vol. x. p. 540, no. 63 -.Dillw. 



Descr. Cat. p. 466, no. 61 : v. Desk, in loc. 

 Trivia radians, Gray Descr. Cat. p. 16, no. 137. 



Most of the Mazatlan specimens were dead ; but when fresh, 

 it is of a brownish colour, with some of the lines interrupted 



