280 MOLLUSCA OF THE 'challenger' EXPEDITION. [May 6, 



guishable in a few points. In the first place the whorls are not 

 quite so closely coiled, the last is spirally constricted and broader 

 near the aperture, the mouth, in consequence, being larger than in 

 H. tesseUata, and the umbilicus is mere open, exhibiting more of the 

 penultimate volution. 



The species is named after Alexander Selkirk, immortalized by 

 Defoe in his story of Robinson Crusoe. 



3. H. (Amphidoxa) marmorella, Pfeiffer. 

 Hab. Island of Juan Fernandez. 



4. BuLiMus (BoRUs) RosACEus, King. 



Hab. Valparaiso. 



The single specimen appears to have been taken whilst in a state 

 of torpidity, as the aperture is closed with a tough horny epiphragm 

 which is as thick as the operculum of Paludina. 



5. BuLiMus (Corona) melanostoma, Swainsou. 

 Hab. Bahia, Brazil. 



6. BuLiMus (Leptomerus) tenuissimus, Ferussac. 

 Hab. Bahia, Brazil. 



7. Stenogyra (Nothus) bulimoides, Pfeiffer. 

 Hab. Island of Juan Fernandez. 



8. Stenogyra (Nothus) splendidula, Anton. 

 Hab. Island of Juan Fernandez. 



9. TORNATELLINA TROCHIFORMIS, Beck. 



Hab. Juan Fernandez. 



10. TORNATELLINA BILAMELLATA, Anton. 



Hub. Juan Fernandez. 



11. SucciNEA FALKLANDicA. (Plate XXIII. figs. 20-20^.) 



Shell elongate, somewhat solid, arcuately striated ; whorls 4^, 

 very convex, regularly increasing ; aperture ovate, occupying rather 

 more than half the length of the shell. Columella only slightly 

 arcuate, reflexed, forming a minute umbilical rimation, united above 

 to the extremity of the outer lip by a thin callosity. 



Length 15i- millim., width Si ; aperture 8h long, .5 broad. 



Hab. From a hill near the lighthouse, Pembroke Point, Falkland 

 Islands. 



This species might almost be considered a large form of S. ohlonga, 

 Draparnaud, which it much resembles in the convexity of the whorls, 

 depth of the suture, and the proportional length of spire and aperture. 



12. SucciNEA FRAGILIS, King. 



Hab. Island of Juan Fernandez. 



