TESTACELLID^E. 7 



of the mantle under the peristorae of the shell ; combined 

 generative orifice behind and below the right superior tentacle. 

 Shell external, rudimentary, imperforate, ear-shaped, with a 

 subspiral, posterior nucleus. 



Genus DAUDEBARDIA, Hartmann, 1821. 



Animal with longitudinal furrows above the margin of the foot, 

 otherwise resembling Testacella. Usually no caudal mucous pore. 



Shell small, external, perforate, depressed, thin and shining, 

 transparent ; paucispiral, the whorls rapidly increasing. 



Section RUFINA, Clessin. Shell umbilicated. 



Section PSEUDOLIBANIA, Stefani, Shell haliotiform, spire very 

 short, narrowly rimate ; columellar lip slightly reflected over the 

 umbilical slit. 



Section LIBANIA, Bourguignat. Umbilicus covered in the 

 adult. 



Section ISSELTA, Bourguignat, Shell perforated. Animal with 

 caudal mucous pore. 



Genus CHLAMYDEPIIORUS, Binney, 1879. 



Mantle covering the whole body, with an orifice on the centre 

 of the back near the tail, enclosing a solid, internal shelly plate ; 

 no caudal mucous pore ; position of the genital orifice unknown. 



? Genus PLECTROPHORUS, Ferussac, 1819. 



Animal elongated, subcylindrical, with a tough dorsal anterior 

 integument or mantle, under which is the pulmonary cavity, 

 having its orifice on the right side, with the anal orifice near it ; 

 there is a second long and narrow dorsal posterior mantle, and 

 an external rudimentary conical, non-spiral shell near the pos- 

 terior extremity ; upper tentacles longest, oculiferous, retractile. 



This animal, figured by Ferussac and said to inhabit Teneriffe, 

 has not been recognized by collectors ; the double armor of the 

 back and the conical shell are both improbable-looking char- 

 acters. 



Genus SELENOCHLAMYS. Bottger, 1883. 



Animal resembling Daudebardia, but without a shell ; mantle 

 small, the surface divided by longitudinal sulcatious ; tail short, 

 compressed, carinated ; foot narrow, tripartite. 



