466 MAZATLAN UNIVALVES 



Hob. Mazatlan ; extremely rare ; L'pool Col. 

 Tablet 2121 contains 3 sp. shewing the extremes of variation. 



593 OLIVA ? VENULATA, Lam. 



An. s. Vert. vol. x. p. 611, no. 13. Mice, in Zeit.f. Mai. 1851, 

 p. 23, no. 103. C. B. Ad. Pan. Shells, p. 56, no. 40. 



? =Oliva venulata, Duel. Mon. Oliv. pi. 16, f. 5, 6. 



+ Oliva araneosa, C. B. Ad. Pan. Shells, p. 49, no. 33 ; (?non 

 Lam.) 



? + O. Julieta, Wee. in Zelt. f. Mai. 1851, p. 23, no. 102. 

 P. P. C. Cat. Prov. : (non Duel.) 



= Oliva reticularis, var., Rue. Condi. Ic. pi. 10, f. 165, d, g. 



1 Che true O. Julieta was not found in this collection. Whether 

 Menke's shell was the tru'e one imported, or whether he made 

 the same mistake that I had copied, cannot be certainly told. 

 His description suits best with the dark variety of this species. . 

 The O. venulata and O. araneosa of Prof. Adams, are separated, 

 from single specimens of each, "principally by the short, dark 

 brown, bent lines of the former." This character is variable. 

 Whether the O. venulata of Duel, is that of Lam. and whether 

 either or both of them represent this, the Pacific analogue of 

 O. reticularis, is also a matter of doubt. 



Shell going through the same changes of pattern as O. Mel- 

 chersi, but ordinarily much smaller ; 1'2 in. being the usual size 

 of large specimens. The prevailing tint is a yellowish olive, with 

 purple brown markings ; rarely of a general greenish yellow, 

 very rarely dark brown. The triangulation is less common 

 and distinct in this species ; and the dark lines often run into 

 spots resembling O. Julieta. The shape is intermediate be- 

 tween O. reticularis proper and O. Melchersi. It has a less 

 elevated spire than the latter, with the angulation very slight 

 and nearer the shoulder. The infrasutural pencilings are 

 generally, but not always, present. Very fine parietal denticu- 

 lations sometimes appear in the adult, but are*generally absent 

 There is usually a purple or chesnut tinge on the lower coin 

 mellar plaits, the upper one being always left white, or at le 

 of a lighter shade. A remarkably large specimen measu 

 long. 1*5, long. spir. "27, lot. '68, div. 90. 



Hob. Panama, extremely rare, C. B. Adams. Mazai 

 not uncommon ; L'pool Col. 



