136 MANUAL OF NATURAL HISTORY. 



him annular, with an internal process ; shell 

 spiral, hyaline, sub-turreted ; aperture en- 

 tire in front. Marine. 



51. FAMILY. Macgillivrayias (Macgillivrayiidae). 



Tentacles four (?), nearly equal ; eyes (?) ; 

 mantle with an elongate siphon in front ; 

 foot large, produced behind ; a float (?) ; oper- 

 culum annular, with an internal process ; 

 shell spiral, sub-globose, horny, sub-pellucid. 

 Pelagian. 



52. FAMILY. Oceanic-Snails (lanthinidse). Ten- 



tacles subulate, with pedicles at their outer 

 bases ; eyes none ; foot small, flat, with a 

 vesicular appendage on hind part ; shell 

 thin, turbinate, violet ; aperture sub-quad- 

 rate ; columella straight ; outer lip notched. 

 Oceanic. 



II. ORDER. SCUTIBRANCHS (Scutibranchiata). 



Gills of two series of lamellae, forming one or 

 two series over back of neck, or on under edge of 

 mantle round foot; shell spiral, or symmetrical 

 and conical. 



I. SUB-ORDER. PEDUNCLE-EYED SCUTIBRAJTCHS 

 (Podophthalniata). 



Eyes pedicelled, separate from the tentacles ; 

 teeth numerous, lateral ones reniform, very numer- 

 ous, crowded. 

 ]. FAMILY. Wreath-Shells (Turbinidse). Foot with 



