UMBRELLID^. 367 



of Pleurobrauchasa ; anal opening behind the base of the gill ; 

 gill large, bipinnate, fully exposed on the right side, between 

 the mantle and the foot. Distr. — K. obesa, Yerrill. Atlantic 

 Coast, United States. 



PosTEROBRANCH^A, d'Orbigny. 



Distr. — P. maculata, d'Orbignj^ (Ixxxix, 91). Coast of Chili. 



Animal shell-less; oval, depressed, covered by a mantle 

 broader than the foot ; foot oblong, bilobed behind ; branchial 

 plume on the left side, projecting posteriorly ; reproductive 

 orifice in front of gill, excretory behind ; proboscis covered by 

 a broad bilobed veil ; no dorsal tentacles. 



RuNciNA (Forbes), Hancock. 



Syn. — ? Pelta, Quartr. (not Beck). 



Distr. — On Confervas near high-water mark, Torbay ; feeds 

 apparentl}^ on Diatomacese. B. Hancocki, Forbes (Ixxxix, 84 ; 

 xci, 44). 



Animal minute, slug-like, with a distinct mantle ; eyes sessile 

 on the front part of the mantle ; no tentacles ; gills three, slightly 

 plumose, placed with the vent on the right side, at the hinder 

 part of the back, beneath the mantle ; gizzard armed ; reproduc- 

 tive organs on the right side. Dentition (xiii, TO). 



Neda, H. and A. Adams. 



Distr. — N. luniceps, Cuv. (Ixxxix, 85'. South Europe. 



Animal shell-less ; mouth terminating a proboscis, which is 

 long and thin ; oral veil half-moon shaped, with two lateral 

 recurved tentacles. 



SusANiA, Gray. 



Distr. — S.testudinaria, Phil. (Ixxxix, 86). 



Mantle verj^ large, broadly margining the foot, vesicular, 

 deeply notched in front ; frontal veil between the base of the 

 tentacles and mouth large and oblong ; foot oblong, rather 

 narrow. Shell verj'^ small. 



Family UMBRELLID^. 



Shell depressed patelliform, thin, calcareous. 



Tentacles dorsal, ear-like, with plicate cavities at their bases ; 

 mouth proboscidiform, retractile, covered by a small oral veil 

 with moderate labial appendages, and concealed in the notch at 

 the fore-part of the foot. Foot large and thick^ deeply fissured 

 in front, the sides tubercular. 



Umbrella, Lam. 

 Chinese umbrella-shell. 



S>jn. — Operculatum, Linn. (part). Acardo, Lam. Gastroplax, 

 Bl. 



