54 ZOOLOGY OF THE VOYAGE OP H.M.S. SAMARANG. 



9. IANTHINEA. 



44. IANTHINA, Lamarck. 



1. Ianthina striolata. PL XI. Pig. 9. Ianth. testa subgloboso-ovata, spira brevi, suturis parum 

 impressis, anfractibus rotundatis, spiraliter irnpresso-striatis, striis tenuibus, flexuosis, apertura orbiculari- 

 ovata ; pallide violacea. 



Hab. Pacific Ocean. 



Several examples were collected of this species, as well as of I. globosa, to which it is so 

 closely allied. It differs in having the spire less depressed and the aperture less dilated in 

 front, whilst the spiral striae are peculiar and the shell is uniformly of smaller size. 



2. Ianthina planispirata. PI. XI. Pig. 10. Ianth. testa, discoidea, spira depressa, plano-convexa, 

 anfractibus ad peripheriam subacute rotundata, apertura latiuscula, antice leviter sinuata ; intense violacea, 

 apicem versus pallidiore. 



Hab. Atlantic Ocean. 



Chiefly distinguished by its narrow compressed mode of convolution, by which the spire 

 is unusually depressed. 



10. NERITACEA. 



45. NATICA, Lamarck. 



1. Natica maceoteemis. PI. XIII. Pig. 9. Nat. testa, subglobosa, spira depressa, perarnpliter 

 urnbilicata, umbilico patente, profundissimo, infundibuliformi, anfractibus convexiSj lsevibus, politis, apertura 

 semiorbiculari ; virescente-alba. 



Hab. Coast of Borneo. 



The Natica melanostoma (PI. XIX. Fig. 7) is furnished with a strong coriaceous foot, well 

 developed in front, by means of which it perforates the sand, while its tentacles are pro- 

 tected ; but when the tide rises and covers the sands, the large side lobes and dilated hind 

 part of the foot are expanded, and the Natica flaps along above the sand. A great peculiarity 

 in the animal of this family is the existence of an operculigerous lobe, which in the polished 

 species nearly covers the shell, and is seen in our figure mounting up behind and partly 

 covering the sides. In Sigaretus this lobe is extended entirely across, and covers the shell, 

 while the operculum is rudimentary ; in Coriocella it not only encloses the shell, but extends 

 beyond it in front, and has been erroneously termed the mantle. 



46. SIGARETUS, Lamarck. 

 1. Sigaeetus acuminatus. PI. XIII. Pig. 8. Sig. testa oblongo-ovata, ventricosa, subumbilicata, 



