324 LITIOPINiE. 



Genus HOLCOSTOMA, H. and A. Adams. 



Shell ovate, thin ; spire short, acuminate, suture chan- 

 nelled ; aperture obpyriform, posteriorly canaliculated, 

 anteriorly emarginate ; columella arcuate, smooth, with a 

 posterior callosity ; outer lip expanded, the margin 

 everted, posteriorly free and ascending on the body- 

 whorl. 



Ex. H. piligerum, Philippi,-^\. 33, fig. 4. 



The shell on which we have founded this genus differs 

 from Qiioyia and Planaxis in being thin, and in the aper- 

 ture being furnished with a posterior canal which extends 

 up the last whorl ; it is covered with an epidermis cu- 

 riously adorned with rows of golden bristles. 



Sub-fam. LITIOPIN^. 



Sides of the foot and operculigerous lobe furnished 

 with tentacular filaments. Operculum horny, of many 

 whorls. 



Pelagian. 



Genus LITIOPA, Rang. 



Shell thin, horny, semipellucid, conoidal ; spire acute, 

 whorls rounded, the last large ; aperture oval, emarginate 

 anteriorly ; outer lip thin, simple, acute. 



Syn. Bomb3'xinus, BHanger, Lesson. 



Ex. L. melanostoma, Eydoux and Soiileyet, pi. 34, 

 fig. 5. Shell, L. bombyx. Rang. fig. 5, a. 



The singular little oceanic Mollusks which constitute 

 this genus have the power of spinning glutinous threads 



