460 MANUAL OF THE MOLLXJSCA. 



MoNTACUTA, Turton. 



Dedicated to Colonel George Montagu, tlie most distinguislied 

 of the earlier Englisli malacologists. 



Type, M. substriata. PI. XIX., Fig. 13. 



Shell minute, thin, oblong, anterior side longest ; hinge-line 

 notched ; ligament internal, between 2 laminar, diverging 

 teeth (with, a minute ossicle. Loven.) 



Animal with the mantle open in front ; margins simple ; 

 siphonal orifice single ; foot large and broad, grooved. 



The Montacutce moor themselves by a byssus, or walk freely ; 

 M. S2ihstriata has onlj'' been found attached to the spines of tho 

 purple heart-urchin [Spatangus purpureus) in 5 — 90 fathoms. 

 M. hidentata burrows in the valves of dead oyster-shells. 



Distribution, 3 species. United States, Norway, Britain, 

 ^gean. 



Fossil, 2 species. Pliocene — . Britain. 



Lepton, Turton. 



Etymology, lepton, a minute piece of money (from leptos, thin). 

 Synonym ? Solecardia (eburnea), Conrad, Lower California. 

 Type, L. squamosum. PI. XIX., Fig. 14. Fig. 256. 

 Shell sub-orbicular, compressed, smooth, or shagreened, a 

 little opened at the ends and longest behind; hinge -teeth 0.1 



or 1.1 in front of an angular 

 cartilage notch; lateral teeth 

 2.2 and 1.1. 



Animal with the mantle (m) 



open in front, extending beyond 



the shell, and bearing a fringe 



of filaments, of which one in 



^. „,- , , front it) is very large ; siphon 



Fig. 2o6. Lepton. f \ • \ •^^ I i, • j 



(s) smgle, gills two oa each side, 

 separate ; foot (/) thick, tapering, heeled and grooved, form- 

 ing a sole or creeping disk. (Alder.) 



Suh-genus. Scintilla (Cumingi), Desh. 1856. Small shells 

 resembling Lepton ; minutely punctate ; ligament internal, 

 oblique; hinge-teeth 1. 2; posterior laterals 1. 2. Distribu- 

 tion, 37 species (?), Philippines, North Australia, Panama. 



Distribution, 50 species. United States, Britain, Spain. 

 Laminarian and Coralline Zones. 



Fossil, 5 species. Pliocene — . United States, Britain. 



