220 SCALARID^. 



Distr. — 2 sp. Europe, Greenland. H. atonius, Phil. (Ixv, 

 15, 16). 



Shell planorbiform, with involute spire ; whorls more or less 

 angulated ; mouth clasping both sides of the periphery. Oper- 

 culum few-whorled, nucleus central. 



Body flattened, tentacles wanting, eyes sessile behind the head. 



Cyrculus, Jeffreys. 

 Distr. — C. striatus^ Phil. (Ixvi, 37). Mediterranean. 

 Shell minute, discoidal ; umbilicus large, profound. Oper- 

 culum multispiral, corneous. 



DiscoHELix, Dunker. 



Syn. — Orbis, Lea (not Blainv. or Lacep.). Bifrontia, Desh. 

 Ilaira, H. and A. Adams. Platystoma, Homes. 



Distr. — D. zanclea, Phil. (Ixv, IT, 18). Fossil. Silurian, 

 Liassic, Cretaceous, etc. 



The genus was projDosed for a liassic, discoidal shell, composed 

 of quadrangular whorls, carinated and more or less crenulated 

 on the upper and lower edges of the back, on which the striae of 

 growth are insinuated backwards. 



Ophileta, Yanuxem. 



Syn. — Cyclogyra,Wood. Planaria, Brown. Discohelix, Adams 

 and Chemn. 



Shell planorbiform, discoidal, whorls numerous, slender, in 

 contact. 



Proposed for a palaeozoic fossil of New York (0. levata, Hall, 

 Ixv, 19^ ; to which may be added the recent Discohelicc foliacea, 

 Phil. (Ixiv, 88, 89). 



EccYLiOMPHALUS, Portlock, 1843. 



Syn. — Serpularia, Roemer. Phanerotinus (partim), Sowb., 

 1842. 



Distr. — Fossil. Palaeozoic, a few species. E. serpula^ Kon. 

 (Ixv, 20). 



Shell discoidal, whorls few, in the same plane, widely disso- 

 lute ; flattened above, rounded beneath. 



Family SCALARID^. 



Characters those of the only genus. These mollusks are closely 

 related to the lanthinae, of which they may be regarded as 

 creeping representatives, on the one side, and to Turritella as 

 well, by the form of their shell. Dentition xi, 36-38). 



ScALARiA, Lam. 

 JEtym.—Scalaris, like a ladder. Wentle-trap. 

 Syn. — Sthenorytis, Compsopleura and Scalarina, Conr. 



