860 Report oF THE STATE GEOLOGIST. 
the deltidial plates have almost invariably been displaced. The 
muscular scars of this valve are deep and sharply defined, but 
restricted to the posterior portion of the shell. In the brachial 
valve, the hinge-plate is elevated into a stout, erect, subcylindrical 
cardinal process, whose posterior face is grooved and striated. 
Brachidium extending for nearly the entire length of the valves ; 
jugal processes depressed, long and convergent; descending 
lamellz arising at an angle from the crura; ascending lamellz 
deeply reflected. Impressions of the adductor muscles long, 
narrow and obscure. 
Type, Megalanteris Archiaci, de Verneuil. 
Distribution. Devonian. 
Enantiosphen, Whidborne. 1893. 
Shells large, with smooth biconvex valves having broadly 
introverted margins; general external aspect as in MrcaLanrEris. 
Interior with a strong ventral median septum. 
Fic. 493. Fic. 494. 
Fias. 493, 494. Enantiosphen Vicaryi, Davidson (sp.) 
(Davipson.) 
Type, Znantiosphen Vicaryi, Davidson (sp.) 
Middle Devonian (Torquay). 
Cryptonella, Hall. 1861. 
(Plate 52, figs. 16-23.) 
Valves subequally convex ; elongate-oval in outline, broadest 
in the pallial region. Pedicle-valve with prominent, erect or 
slightly incurved umbo ; deltidial plates well developed ; foramen 
circular, apical, rarely encroaching upon the umbo, or becoming 
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