Mr. U. Etheridge on Carboniferous LameUihranchtata. 431 



Genus SciiizODUS, King, 1844, 

 Aunala Nat. Ilist. 1844, xiv. p. 313; Permian Fo&sils, 185(), p. iSi. 



Schizodus Saheri'j sp. nov. 



Schizixiiis, sp. (Salter), Rev. T. Brown, Trans. Roy. Soc. Edinb. 18G1, 

 xxii. p. 092, fig-s. 1-3. 



Sj)cc. char. Very inequilateral, convex and prominent in 

 the umbonal region ; anterior side rounded ; posterior side 

 longer and more compressed than the anterior, slightly ti-un- 

 cated obliquely, narrowed by the convergence of the dorsal 

 and ventral margins ; ventral margin gently rounded ; an 

 obtusely rounded and curved diagonal ridge proceeds from the 

 beak of eacli valve to the po.stero-ventral margin, enclosing 

 between it and the dorsal margin a narrow, slightly concave, 

 posterior slope. Beaks pronounced, prominent, slightly in- 

 curv^ed towards the anterior side ; valves very prominent and 

 convex in the umbonal region, rapidly arching downw^ards to 

 the rounded ventral margin. In the right valve the anterior 

 tooth is inclined a little obliquely towards the anterior side ; 

 the posterior tooth is elongated. In the left valve the large 

 central tooth is very prominent, thick, plain, and projects 

 somewhat outwards from the umbonal cavity ; although not 

 bifid, the ventral margin of this tooth appears in some speci- 

 mens to be veiy slightly concave, tliereby indicating a ten- 

 dency towards the bifid form ; anterior and posterior teeth 

 obscure. The scar of the anterior adductor is oval, and 

 attenuated towards its dorsal extremity ; the posterior im- 

 pression also oval, but rather larger tlian the anterior. Pallial 

 line well defined on the anterior and posterior sides, less so in 

 the middle of its course ; an internal curved ridge extends 

 from the umbonal cavity on the posterior side obliquely 

 towards the postero-ventral margin, and nearly corresponds in 

 position with the diagonal ridge. Surface of the shell towards 

 the ventral margin is marked by several well-defined laminai 

 of growth, between which and over the general surfiice are 

 close fine strife, usually only faintly preserved. 



Ohs. In connexion with this shell, the Rev. T. Brown 

 makes the following remarks in his paper on the " Mountain 

 Limestone and Lower Carboniferous Rocks of the Fifeshire 

 Coast, &c."* : — " Dr. Fleming, to whom I formerly submitted 

 this shell, considered it to be the Anatina atteyuiata of M'Coy, 

 but held that it had been erroneously refeiTed to that genus. 

 He possessed numerous specimens from a bed near Colinton, 

 where it occurs in such abundance as to suggest the idea of its 



* Traus. Rny. Soc. Edinb. xxii. p. 303. 



