13S 



MANUAL OF THE MOLLUSCA. 



Animal ^dth. an elongated (non- retractile ?) proboscis ; tentacles long and 

 slender, with sessile eyes at their outer bases ; sides plain ; foot narrow, 

 elongated behind. (Adams.) Related to scalaria ? 



l^lost of the phori attach foreign substances to the margins of their shells, 

 as they grow ; pai'ticular species affecting stones, whilst others prefer sheUs or 

 corals. They are called " mineralogists," and " conchologists," by collectors ; 

 P. solans and P. indicus ai'e nearly or quite free from these disguises. They 

 are said to fi-equent rough bottoms, and to scramble over the ground, like the 

 strombs, rather than glide evenly. 



Distr., 9 sp. W. Indies, India, Malacca, Philippines, China, W. America. 



Fossil,!^ s^. ChaUf? — Eocene — . Brit., France. Shells extremely hie 

 the recent phonis, are met with even in the carb. limestone. 



Lacuna, Turton. ; 



Etpn., lacuna, a fissure. j 



Tf/pe, L. pallidula, PI. IX., fig. 16. Syn., medoria, Gray. I 



Shell, turbinated, thin ; aperture semi-lunar ; columella flattened, with ] 



an umbilical fissure. Operc. pauci-spiral. 



Animal, operculigerous lobe furnished with lateral wings and tentacular 



filaments. Teeth, 5 cusped ; uncini 1, 2 dentated, 3 simple. Spawn [pothecd) \ 



vermiform, thick, semicircular. Range, low- water — 50 fathoms. 



Distr., Northern shores, Norway, Brit., Spain. Fossil, 1 sp. Glacial j 



beds. Scotland, vj 



? LiTioPA, Rang. i| 



Etpn., litos, simple, ope, aperture. f 1 



Type, L. bombix. PI. IX., fig. 24. *! 



Shell minute, pointed ; aperture slightly notched in front ; outer lip sim- i 



pie, thin ; inner lip reflected. Operc. spiral. 



Distr., Atlantic, Medit., on floating sea-weed, to which they adhere by ] 



threads. Fossil, 1 sp. Miocene (Crag.). 



RissoA, FremenviUe. i 



Mym., named after Risso,* a French zoologist. 

 Type, R. labiosa, PI. IX., fig, 17. Syn., cingula, Flem, 

 Shell minute, white or horny ; conical, pointed, many-whirled ; smooth, 



ribbed, or cancellated ; aperture rounded ; peristome entiie, continuous ; outer 



lip slightly expanded and thickened. Operc. sub-spiral. 



The animal has long, slender tentacles, with eyes on small prominences 



near their outer bases ; the foot is pointed behind ; the operculigerous lobe 



has a wing-like process and a filament {cirrus) on each side. Lingual teeth 



single, sub-quadrate, hooked, dentated ; uncini 3 ; 1 dentated, 2, 3, claw- 



* It is much to be regretted that some modern naturalists have tried to find out 

 and bring into use the obscure genera of Risso, and the worthless fabrications of Mont- 

 fort and Raflnesque, which had better have remained unknown. 



