CONCHIFERA. 429 



(Dr. Mig-hels.) Fossil, Pliocene — . (Crag and Glacial deposits.) 

 England, Belgium. 



Fig. 220. Yoldia limatula (after Barrett). 



SoLEXELLA, Sowerby. 



Tijpe, S. Korrisii, PI. XVII., Fig. 22. S. ornata, Fig. 23. 



Synonyms, Malletia, Desm. Ctenoconcha, Gray. Neilo, 

 Adams. 



SheU oval, or ark-shaped, compressed, smootli or concentri- 

 cally furrowed, epidermis olive ; ligament external, elongated, 

 prominent : hinge with an anterior and posterior series of fine 

 sharp teeth ; interior sub-nacreous ; pallial sinus large and 

 deep ; anterior adductor giving off a long oblique pedal line. 



Animal like Yoldia; mantle-margins slightly fringed and 

 furnished with ventral lobes ; siphonal tubes united, long, and 

 slender, completely retractile; palpi appendiculated, convoluted, 

 as long as the shell ; gills narrow, posterior ; foot deeply cleft ; 

 forming an oval disk, even-margined and striated across. 



Distribution, 2 species. Valparaiso, New Zealand (shell like 

 B. ornata). 



Fossil, 1 species. Miocene. Point Desire, Patagonia. 



? SoLEMYA, Lamarck. 



Type, S. togata, PI. XXII., Fig. 17. 



Synonym, Solenomya, Menke. 



Shell elongated, cylindrical, gaping at each end ; epidermis 

 dark, horny, extending beyond the margins ; umbones poste- 

 rior ; hinge edentulous ; ligament concealed ; pallial line 

 obscure. Outer layer of long prismatic cells, nearly parallel 

 with the surface, and mingled with dark cells, as in Pinna ; 

 inner layer also cellular. 



Animal with the mantle lobes united behind, with a single 

 siphonal orifice, hour-glass shape, and cirrated ; foot probos- 

 cidiform, truncated and fringed at the end ; gills forming a 

 single plume on each side, with the lamintB free to the base ; 

 palpi long and narrow, nearly free. 



