578 



Forty- fifth Rep oft on the State Museum. 



anterior scars are coalesced ; the cardinal scars in the as other 

 valve. 



Type, Pseudocrania antiquissima, Eichwald (sp.). (Lower 

 Silurian.) 



Subgenus Craniella, (Ehlert. 1888. 

 (Plate 7, Figs. 4, 8.) 



Shell somewhat irregular, outline subcircular or subquadrangu- 

 lar. Lower valve thin, adhering by its entire surface; upper 

 valve conoidal, more or less elevated ; apex subcentral, posterior ; 



interior of the upper valve without 

 a well defined border ; impressions of 

 the adductors large, very distinct, 

 four in number, of which the poste- 

 rior two are quite distant, the anterior 

 two subcentral, someAvhat smaller, 

 closely approximate or even con- 

 fluent; from near each of the pos- 

 terior impressions starts a vascular 

 sinus, which is broad, strongly 

 sinuous near its point of departure, 

 narrowing gradually in following the contour of the valve, 

 emitting from its marginal side dichotomizing secondary branches. 

 Type, Craniella Meduanensis, (Ehlert. 

 Distribution. Lower Silurian to Devonian. 



Fig. 268 — Craniella Meduanensis . 



After QChlert. 



Internal cast of upper valve. 



Subgenus Cardino crania, Waagen. 1885. 

 (Plate 7, Figs. 9, 10.) 



Shells attached ; posterior margin straight, set off from the 

 rest of the outline by strong post-lateral indentations. Interior 

 with a thin triangular plate, broad at its base where attached in 

 the cardinal region; supported by a low median septum. 

 Muscular impressions unknown. 



Type, Cardinocrcmia Indica, Waagen. (Permo-carboniferous, 

 India.) 



Pholidops, Hall. 1859. 



(Plate 7, Figs. 14-22.) 



Synonyms; PatelHtes, Schlotheim, ls2<>; ( i r<i)ii<>j>.s. Hall. 1859. 



Shells small, patellifornij eqtfivalve, equjeonvex, inarticulate, 



unattached, Outline oval or subelliptical; apex subcentral, 



130 



