118 



NACELLA. 



The series of this species before me is very extensive, and shows 

 such remarkable variations that it is not unlikely that all described 

 species of Patinella will be found to be connected by intermediate 

 forms. The specimens of cenea may be separated by moderately 

 definite characters into three varietal types: (1) typical ^NEA, de- 

 fined above ; (2) var. DEAURATA ; and (3) var. MAGELLANICA. 



Var. DEAURATA Gmelin. PI. 46, figs. 28-36. 



Shell rather thin, oblong, depressed, the apex in front of the an- 

 terior third, somewhat curving forward. 



Interior showing bronze-brown radiating stripes on a light ground, 

 the central area reddish or blackish bronze, oblong, generally dis- 

 tinct. Length 56, breadth 38, alt. 16 mill. 



Straits of Magellan. 



P. deaurata GMEL. Syst. Nat. xiii, p. 3703. P. cymbularia 

 DELESSERT (not Lam.) Rec. de Coq. Lam'k., t. 23, f. 8. P. fer- 

 ruginea SOWB., Genera of Shells, Patella, f. 4. P. delessertii PHIL., 

 Abbild. iii, p. 9, t, 1, f. 5. P. varicosa REEVE, Conch. Icon. f. 21. 

 ? P. adunca PERRY, Conchology, t. 43, f. 5.Nacella strigatella 

 ROCHEBR. & MAB., Mission du Cap Horn, Moll., p. 96, t, 5, f. 8. 

 P.ferruginea WOOD, Index, Patella, f. 32. 



Distinguished from typical cenea by being more depressed, thinner, 

 the apex more anterior. The riblets of the outer surface are some- 

 times nearly obsolete, sometimes strongly developed ; and they may 

 be either smooth or granose, the grains having a scale-like character, 

 as in cenea. 



I am much disposed to consider P. polaris of Martens and Pfeffer 

 a form of this variety. 



Specimens in which the stripes anastomose and branch were 

 called varicosa by Reeve (pi. 46, figs. 33). I surmise that Gmelin's 

 P.flaminea (Syst. xiii, p. 3716) and Woods' P. flaminea (Index, pi. 

 38, f. 71) are identical with varicosa. 



The outer surface is frequently bluish-white, ribs yellowish, but 

 sometimes the ribs are rust-brown. I have seen specimens of a clear 

 yellow, lacking radiating stripes ; and others occur in which the 

 stripes unite to make a uniform dark brown shell. 



This variety is further modified into oblong forms having the apex 

 decidedly curved over, and near to the anterior end. Such a form 

 is that called cymbularia by Delessert (pi. 44, fig. 20), and striga- 



