NACELLA. 121 



P. polaris approaches certain forms of P. cenea var. deaurata, but 

 the ribs are more obsolete and the interior darker than is usually the 

 case in that form. 



N. KERGUELENSIS E. A. Smith. PI. 43, figs. 7, 8. 



Shell oval, a little narrowed in front, rather elevated convex, the 

 apex prominent and well toward the front, especially in the young ; 

 widely radiately ribbed, the ribs little prominent, and often with 

 interstitial smaller riblets ; sculptured with elegantly undulating and 

 close concentric growth-lines. Exterior bluish-ashen, the ribs 

 usually darker, toward the apex ferrugineous in eroded examples. 

 Interior bronze-brown, generally paler toward the margin, which is 

 a little undulating ; muscle-scar visible ; a large example measures, 



Length 82, breadth 70, alt. 45 mill. (Smith.) 



Swain's Bay and Royal Sound, Kerguelen Island, in about 1 fm. 



P. ferruginea (Sows. MS. in Mus. Cuming) REEVE, Conch. Icon., 

 f. 40, not P. ferruginea Gmel. nor P. ferruginea Sowb. Genera of 

 Shells, f. 4. P. Jcerguelensis E. A. SMITH, Zool. of Kerguelen Id., 

 Moll., in Philos. Trans. Roy. Soc. Lond. vol. 168, p. 177, t. ix, f. 13, 

 13a, (1879.) 



Differs from P. wnea Martyn in having the shell less prominently 

 costated, differently colored, and in the apex being very prominent 

 and much curved over, so as to give it a capuliform appearance, a 

 character constant in all specimens, young and old, elevated and de- 

 pressed ; it also differs in the coloration of the animal. (Smith.) 



N. FUEGIENSIS Reeve. PL 49, figs. 28, 29, 30, 31. 



Shell oval, rather thin, semitransparent, rather compressly raised ; 

 apex rounded, inclined anteriorly ; radiately ridged, ridges thin, 

 numerous, densely crossed with concentric striae ; greenish, more or 

 less stained and blotched with chestnut-brown, apex bronze ; interior 

 iridescent-bronze, radiately grooved, grooves sometimes partially 

 obsolete. (Reeve.) 



Tierra del Fuego ; Orange Bay; Falkland Is. ; Royal Sound and 

 Swain's Bay, Kerguelen Id., everywhere common on the submerged 

 fronds of long floating kelp (Macrocystis) bordering the shore. 



P. fuegiensis REEVE, Conch. Icon., f. 73, (1855). Patella 

 (Patinella) fuegiensis SMITH, Philos. Trans, vol. 168, p. 180, t. 9, f. 

 14, 14a. P. fuegiensis ROCHEBRUNE & MABILLE, Miss. Sci. du 

 Cap Horn, Moll., p. 95. 



