234 MAZATLAN UNIVALVES 



thority. Tlie differences in the Mazatlan shells appear too 

 trifling to found specific distinction upon them. The characters 

 of tlie shell can only be seen in the young state ; in its ordinary 

 form, it has the external aspect of the British Osilinus (Troc- 

 hocochlea) lineatus ; from which the umbilicated axis and 

 nodulous columella at once distinguish it. Long. 1*17, lat. 1'08, 

 div. 70. 



Hob. China, Mus. Cuming. [?] Mazatlan ; very rare; 

 L'pool Col. 



Tablet 1130 contains the largest and smallest specimen. 

 1131, 1 sp. lip tinged with orange. 



292. OMPHALIUS VIEIDULUS, Gmel. 



Trochus viridulus, G-mel. p. 3574 Schreib. Conch, vol. i. 



p. 245. Dillw. Descr. Cat. p. 777, no. 42 Wood 2nd. Test. 



no. 42, pi. 28, p. 136, 



Omphalius viridulus, H. fy A. Ad. Gen. i. 429. 

 Globulus ex viridi et rubro variegatus, Chemn. vol. v. p. 114, 



pi. 171, f. 1677 : (non Trochus variegatus, Chemn. p. 104, 



f. 1661-2: Dillw. p, 774, no. 35: =T. Capensis, Gmel. 



p. 3573 : Hob. Tape of Good Hope.') 

 Phorcus variegatus, A. Ad. in Proc. Zool. Soc. 1851, p. 156. 

 = Trochus Brazilianus, Mke. teste A. Ad. loc. cit. 

 + Trochus Byronianus, Wood Suppl. p. 16, pi) 5, no. 17. 



(Hob. 'Sandwich Is.') 

 Var. = Trochus reticulatus, Gould, ms. Cat. 

 Comp. O. cruciatus, Gmel. (non Linn, teste Phil., Brazils) : 



= O. Brazilianus, Mke. = Q. Byronensis, teste Mus. Cum. 



The single specimen which Mr. Cuming assigns to this very 

 variable species, differs from all forms of O. ligulatus in the 

 following particulars. Spiral lirae, both above and below, much 

 fewer, with broad interspaces. Umbilicus somewhat cork- 

 screw shaped, the parietal callosity being farther off from 

 the centre, while the spiral ridge is nearer to it. It appears 

 also to want the seminodulous callous ridge at the base of 

 the labrum. Colour dull red, slightly spotted with orange. 

 Long. '64, lat. '76, div. 90. 

 Hob. Mazatlan, Col. Jewett. Do. ; 1 dead sp. ; L'pool Col. 



San Diego ; very red variety ; Lieut. Webb. 



Tablet 1132 contains the specimen. 



