126 



Characters of 



Lintrulepis, 



Hall. 



Lingulepis 



Gregwa 



described. 



LINGULEPIS, Hall. 



The late Professor James Hall described from the St. Croix Sandstones 

 of the Mississippi valley a genus of Brachiopods, of which examples arc 

 found in. the Lower Etcheminian Fauna, It is described as ' shells lin- 

 guloid, inequivalve, equilateral, oval-spa tulate or spatulate, muscular im- 

 pressions in one valve (dorsal) flabelliform, in the other tripartite, the 

 lateral divisions larger. Shell corneous, phosphatic. Lingula pinni 

 formis, Owen sp. is the type. 



Hall's figure represents the callus as extending one half of the length 

 of the ventral valve, and a little more than half of the length of the dor- 

 sal. Walcott makes this species synonymous with L. acuminata, Conrad, 

 from the Potsdam sandstone ; in this the callus of the ventral valve ex- 

 tends two thirds toward the front and that of the dorsal also to this dis- 

 tance. The Etcheminian forms carry out the feature observed for others 

 of its genus, viz.: of a long callus to the dorsal valve ; this, in the species 

 named below, is proportionately longer than in the last named species and 

 much longer than in the other. Valves of this genus are common in 

 some portions of the Lower Etcheminian, but none have been found in 

 the Upper. We have found no flabelliform impression in the dorsal 

 valve, such as Professor Hall described for the type of the genus ; nor in 

 the ventral, lateral septa exceeding the callus in length. 



LINGULEPIS GREGWA. PI. IX, figs. 3 a-f. 



Lingulella Gregwa, n.sp. Bull. Nat. Hist. Soc. of N.B., vol. iv, p. 199, 

 pi. I, figs. 1 a to/. 



Valves pentagonally oval except for the long projecting beak of the 

 ventral valve. 



Ventral valve with a long somewhat acuminate apex, the rest of the 

 valve evenly rounded. Deltidial ridges scarcely distinct from the areal 

 border ; both are crossed by striae directed forward toward the pedicle 

 groove. The interior of this valve has the group of central scars well 

 forward, and shows impressions of vascular trunks, arching toward the 

 front margin. 



The dorsal valve is pentangular ovate and more strongly arched longi- 

 tudinally than the ventral. The interior of this valve is remarkable for 

 the very advanced position of the central group of muscles, which are 

 about one-third from the front of the valve ; this gives the raised band 

 on which they are placed a ribbon-like appearance. The pits of the um- 

 bonal muscles and the posterior laterals are visible on the interior of this 



