33 



ribs lighter; adults more of an even gray all over. Edge of shell 

 even, smooth, with a green or light green border within. 



Inside pure white in old shells, but with an irregular green or 

 brown central spot in the younger stages. 



Length 70, breadth 60, alt. 23 mill. 



Peru to Chili. 



Patella viridula, LAM. An. s. Vert, vii, p. 539 DELESSERT, 

 Recueil, t. 23, f. 2 RVE. Conch. Icon. f. 26 a, b, c. Lottia viridula 

 OLD., U. S. Expl. Exped. p. 353, t. 30, f. 459. Patella pretrei ORB., 

 Voy. Amer. Merid. p. 481, t. 78, f. 15, 16.? P. (Aemcea f) plana 

 PHIL. Abbild iii, t. 2, f. 3.? A. nisoria PH., Zeitschr. f. Mai. 1846, 

 p. 49 ; Abbild. t. 2, f. 8. 



Differs from Seurria zebrina in the character of the painting, and 

 in the sculpture. The viridula lacks the cordon of branchial papillae 

 possessed by the other species. 



Orbigny's P. pretrei (PI. 34, figs. 9, 10) is evidently a variety. 

 A. plana Phil, may perhaps be the young of this species ; see under 

 A. araucana. A. nisoria probably belongs here also. The descrip- 

 tion is as follows. 



Var. NISORIA Philippi. PL 4, figs. 82, 83, 84. 



Shell solid ; suborbicular, elevated-conical, radiately obscurely 

 ribbed-striate ; whitish, subtessellated with lints, flames and dots of 

 brown ; apex situated at the front two-fifths of the length. Inside 

 white, often brown in the cavity, the border dotted with brown. 

 Length 15, breadth 14, alt. 6 mill. The impressed radii are irregu- 

 lar, and sometimes there is a weak indication of about 16 radial 

 ribs. The nearly circular form, the height and thickness of the 

 shell, as well as the coloration, mark out this species from its allies. 

 (PhiL) 



A. CEOILIANA Orbigny. PI. 34, figs. 17, 18, 19, 20, 21, 14, 15, 16. 



Shell solid, oval, elevated, the apex in front of the middle, some- 

 times decidedly anterior ; posterior slope frequently decidedly arched. 

 The surface has 13 to 16 strong elevated radiating ribs, those upon 

 the posterior slope most strongly developed. Color grayish, with 

 several black lines in each intercostal space. Edge of shell more or 

 less strongly crenated by the ribs. 



Inside soiled white, the margin articulated with black. The 

 central area has five or six longitudinal black stripes on a white 

 ground. Length 17, breadth 14, alt. 7 mill. 



3 Falkland Is. ; Strait of Magellan ; Chili. 



