174 IANTHINIDjE. 



low water among Gigartina mammillosa and Corallina 

 officinalis on the Plateau du Four in Lower Brittany, 

 and in M. Martin's collection at Martigues other speci- 

 mens similar to the last from Cape Couronne in the 

 Gulf of Lyons; and I took this species myself at 

 Spezzia. 



It is the most slender of all the Odostomice. My 

 largest specimen (Zetlandic), which is a line and a 

 quarter in length, has a diameter in the widest part 

 equal to one-fifth only of that dimension. 



Family XVII. IANTHI'NHLE, Deshayes. 



Recluzia is the only genus besides Ianthina that has 

 any good claim to be a member of this select and pecu- 

 liar group ; and as the systematic position of the former 

 genus is somewhat doubtful, I will content myself with 

 giving the characters of Ianthina only. 



De Blainville called the family Oxystoma, Brown lan- 

 thinea, and Agassiz Ianthinoidce. 



Genus IAN'THINA* Bolten. PL III. f. 1. 



Body globular, with a short posterior convolution : mantle 

 folded at the base of the shell, and expanding into two irregular 

 flaps or lobes, that probably serve as imperfect natatory organs 

 (" epipodial fins," Morch), and are fringed with fine cilia : head 

 consisting of a thick, cylindrical, and occasionally swollen muz- 

 zle, terminating in a cloven mouth, which is encircled with 

 minute and flexible cilia ; and it is provided with a pair of carti- 

 laginous jaws and a spinous tongue ; this latter organ is armed 

 with very long and awl-shaped uncini or lateral teeth, arranged 

 in two rows, but it has no rhachis or central tooth : tentacles 

 conical, each furnished at its base with a short finger-shaped 



* From its violet colour. 



