SYNTROPHIID^. 807 



HXJENELLA ETHERIDGEI Walcott. 

 Plate LXXXIX, figures 9, 9a. 



Orthis (or Orthisina) sp. Etheridge, 1905, Trans. Roy. Soc. South Australia, vol. 29, p. 2.50, PL XXV, figs. 9 and 10. 



(Described as below and discussed. The specimens represented by figs. 9 and 10 are redrawn in this monograph, 



PI. LXXXIX, figs. 9 and 9a, respectively.) 

 Euenella etheridgei Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 109-110, PL X, figs. 13 and 13a. 



(Described and discussed as below, copying the original descriptions. Figs. 13 and 13a are drawn from the 



specimens represented by figs. 9 and 10 of the preceding reference and are copied in this monograph, PL LXXXIX, 



figs. 9a and 9; respectively.) 



Doctor Etheridge describes the ventral valve as follows: 



Subquadrilateral, convex, the greatest convexity at about midway in the length of the valve, the sinus gradually 

 deepening and widening toward the front, and bounded laterally by ill-defined folds, one on either side, the surface 

 sloping away on either side rapidly to the lateral margins, and at a very much less angle within the sulcus; there are 

 indications of costse on the divaricating folds and in the sulcus. 



The hinge features are hidden in matrix, nor is the umbo distinctly visible. 



He describes the dorsal valve as follows: 



Rotundato-quadrate, the cardinal margin as long as the width of the valve, the surface convex, except on the 

 dorso-lateral alations, where it appears to be flattened. There is a central, acute, or pinched-up fold, produced forward, 

 and expanding as it advances. There are indications of the existence of strong, distinct, subradiating cost*. 



Whether or no this is the brachial valve of the species represented by the preceding form it is at present impossible 

 to say; the two occur in the same bed, however. 



From the study of the various forms of Huenella described herem, I think that the two 

 valves belong to one species, and I take pleasure in naming it after Dr. R. Etheridge, jr. 



Formation and locality. — ^Uiddle ? Cambrian: (315c [Etheridge, 1905, p. 250]) "AichKocyathinse white lime- 

 stone" at Wirrialpa, Flinders Range, South Australia. 



Huenella lesleyi Walcott. 



Text figures 75A-C. 



Huenella lesleyi Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 110, PL X, figs. 12 and 12a. (Characterized 

 and discussed as below as a new species. Figs. 12 and 12a are copied in this monograph as figs. 75B and 75A, 

 respectively.) 



Only the exterior of the valves of this species is known. In form and outline it is most 

 nearly related to Huenella texana (Walcott). It differs from the latter in being broader in 

 proportion to its length, and in having narrow, radiating, rounded ribs over the entire surface. 



" A B 



Figure 75.—IIuenellalesletji'Walcott. A, A', Exterior ofpartly exfoliated dorsal valve(U. S. Nat. Mus. Cat. No.52481b). B, Exterior of ventral 

 valve, the type specimen (U. S. Nat. Mus. Cat. No. 52481a). C, Exterior of ventral valve (U. S. Nat. Mus. Cat. No. 52481c). 

 The specimens represented are from Locality 54e in Blacksmith Fork Canyon, Cache County, Utah. Figures 75A and 75B are copied from 

 Walcott [1908d, PI. X, figs. 12a and 12, respectively]. 



This is probably the oldest Huenella. It occurs 1,025 feet (312.4 m.) below the summit of 

 the Upper Cambrian. Billingsella coloradoen^is (Shumard) and Lingulella manticula (White) 

 occur in the same bed of limestone. 



The specific name is given in honor of the late Dr. J. P. Lesley, state geologist of Pennsylvania. 



Formation and locality. — Upper Cambrian: (54e) About 200 feet (61 m.) above the Middle Cambrian and 

 1,025 feet (212.4 m.) below the top of the Upper Cambrian in limestones forming 3 of the St. Charles formation [Walcott, 

 1908f , p. 193], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. 



