MANUAL OF CONCHOLOGY. 



Family MARGINELLID^E. 



Animal having tentacles arising close together, the eyes on the 

 lower portion or near the middle of the tentacles ; mantle with 

 expanded side-lobes, covering the back of the shell, as in Cyprsea; 

 siphon elongate, simple at base ; foot large, truncate in front, 

 produced behind. Operculum usually none. 



Shell porcellanous, polished, usually smooth, or with longi- 

 tudinal ribs ; spire short or immersed, body-whorl ample ; aper- 

 ture nearly the length of the shell, the outer lip usually with 

 thickened margin, smooth or dentated within, the inner lip with 

 several distinct plaits on the columella. 



Dentition. In possessing rhachidian teeth, without laterals, 

 the lingual armature of Marginella resembles that of Valuta, 

 whilst the shape of the plate and its dentated edge are very 

 similar to that of Mitridse ; lateral teeth being added, however, 

 in the latter family. A single species of Erato (the only one 

 examined), possesses laterals like Trivia in Cypraaidae, and upon 

 this ground the genus has been placed in that family by some 

 systematists (PI. 2, fig. 7). 



The expanded mantle-lobes, covering the shell which thus 

 receives a polished surface, and is devoid of epidermis immedi- 

 ately suggest relationship with the cowries (Cyprae.a), but more 

 particularly with the Olives and Ancillaria, on the one side ; 

 whilst the presence and position of the columellar plaits, as well 

 as the form of many of the species, on the other side, approxi- 

 mates the family to Mitra and Valuta. 



Stimpson created a family Cystiscidse for a little Marginella- 

 like shell dredged by him near the Cape of Good Hope. The 

 animal has an elongated, narrow foot; the head is oblong. 



