548 



Forty- fifth Report on the State Museum. 



into two narrow lateral branches, extending for about one-half 

 the length of the shell. Between them and continuous with 

 their posterior portion, lies a central scar, not extending so far 

 forward, but together with the lateral branches giving the entire 

 muscular impression a strongly tripartite character. There is a 

 low median ridge, elevated along its margins, depressed in the 

 middle ; similar to but fainter than in Lingula anatina. 



In the brachial valve the muscular impressions make a con- 

 spicuous flabelliform scar, extending medially about one-half the 

 length of the shell. The central portion of this scar is accom- 

 panied on either side by broader, partially resolvable lateral 



Figs. 237, 238.— Lingulepis pinniformis. I, lateral scars; c, central scars; 

 s, septum. 



scars, all the subdivisions of the impression coalescing in the 

 unbonal region. There is no septum in this valve. 

 Type, Lingulepis pinniformis, Owen (sp.). 

 Distribution. Cambrian. About six species are known in 

 American faunas. 



Lingulella, Salter. 1866. 

 (Plate 3 ? Figs. 1-4.) 

 Shells linguloid externally. The passage for the pedicle is a 

 sharply defined slit, not merely making a 

 depression upon the surface of the 

 cardinal area but apparently penetrating 

 it from apex to cardinal line. In the 

 interior the pedicle-valve bears two 

 ong, narrow crescentic lateral scars, 

 leiiaDavisi. (Davidson) and shorter, more or less coalesced 

 central scars, somewhat tripartite in outline. 



In the brachial valve are two diverging lateral scars, extending 

 about one-half the Length of the shell, ami incurving at their 



100 



Fig, 239.— Cardinal area of Ldngu- 



