PIIVr.Or.ENY OF FUSUS AND ITS ALLIES. 



29 



often becomes stronger than the others, thus producing a sHght keel, 

 and suggesting the coins stage. 



The ribs are usually thicker and more closeU' crowded than on 

 F. tiirriciilns of the same size, '^lu■^ resemble more the ribs of the 

 adult of that species. A greater crowding is the necessary result of 

 the proportionally larger size of the ribs. 



Two specimens from Ceylon (Phil. Acad.) are of a ruder type than 

 the normal. The t\irricidns whorls recall those of F. rccz'caiiiis rather 

 than those of F. turriculns. The ribs are broad, round and separated 

 only by a depressed line. The sutures are not so deeply impressed as 

 in turriculns, but jmrtake of the character of F. rccvcanus. A faint 

 angulation appears in some of the neanic whorls, which in consequence 

 take on a shouldered expression. This disappears in the last whorl, 

 which is round and ribless with strong primary and slightly weaker 

 secondary spirals. 



It is possible that these specimens represent a loni^icaiidns stage in 

 development of a series beginning with F. reeveanns, and paralleling the 

 series beginning with F. turriculns. If that is the case, these individuals 

 will have to be made the types of a new species. Owing to the meager 

 amount of available material, however, and because no authentic speci- 

 mens of F. rccvcanus have come under observation, no separation will 

 be made at present. 



The Fusus Colus Series. 



: F. longicaudus. F. spj (longicaudits type). 



F. eucosmius. 



F. longicaudus. 

 var. toreumoidcs. 



F. nob His. 



B '■ '7- F. colus. F. turriculus {nobilis type). 



< ]< I 



F. toreumus. \ 

 ''- — F. turriculus. 



F. reeveanus. 



Recent. 



F. Itaitcnsis. 



F. hcnekeni. 



F. muUispiratus. 

 Fusus crcctus. 





O 3 



F. porrectus. 



o 



