808 CAMBEIAN BRACHIOPODA. 



HUENELLA ORIENTALIS (Walcott) . 



Plate CIV, figures 3, 3a-b. 



Syntrophia orientalis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 292. (Characterized and discussed as below as 

 a new species.) 



This species is closely related in form and surface characters to Huenella texana (Walcott) 

 and some forms of H. abnormis (Walcott). It differs from them in details of surface ribs. On 

 ihe dorsal valve there are two or three faintly defined radiating ribs on each side of the median 

 fold, which has obscure ribs upon it. Corresponding ribs occur upon the mesial depression of the 

 ventral valve and the side slopes adjoining the depression. The material representing it is too 

 limited to warrant an identification with any described species. H. orientalis is the trans- 

 Pacific representative of H. texana. 



Formation and locality.— Upper Cambrian: (C64) Upper limestone member of the Kiulung group [Black- 

 welder, 1907a, pp. 37 and 42 (first list of fossils), and fig. 10 (bed 20), p. 38] 2.7 miles (4.3 km.) southwest of Yenchuang, 

 Sintai district. Shantung, China. 



Huenella texana (Walcott). 



Plate cm, figures 1, la-i. 



Camerella sp.? Shumard, 1861, Am. Jour. Sci., 2d ser., vol. 32, p. 221. (Mentioned; see below forcopy.) 

 Syntrophia texana Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 294. (Original mention copied and species dis- 

 cussed as below as a new species.) 



This may be called the plicate representative of the group of species referred to the Syntro- 

 phiidse. It is intimately connected with the smooth forms by a series of shells that vary from 

 16 ribs on a valve to 1; the extremes are shown by Plate CIII, figures Id and le. In form 

 H. texana is much like H. abnormis (Walcott); also in the cross section of its spondylium. 

 They differ in the extravagant development of the plications of H. texana, a feature characteristic 

 of a large series of specimens. 



The average size of the larger shell is width, 8 mm.; length, 6 to 7 mm . 



It is probable that this is the shell referred to by Dr. Shumard [1861, p. 221] as Camerella 

 sp. ?. He said of it: 



There are several specimens of a small brachiopod in the Texas state collection, from the Potsdam sandstone of 

 Morgans Creek, Burnet County, which appear to belong to the genus Camerella recently created by Mr. E. Billings. 

 Unfortunately, however, they consist merely of detached and imperfect valves too much weathered for satisfactory 

 determination and description. 



Formation and locality. — Upper Cambrian: (68) Interbedded sandstone and limestone, Packsaddle Mountain, 

 Llano County; (71) limestone in Cold Creek Canyon, Burnet County; and (69) limestone near Honey Creek, Burnet 

 County; all in Texas. 



Huenella texana LiEviuscuT.ua (Walcott). 



Syntrophia texana Ixviusculus Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 294-295. (Characterized and dis- 

 cussed as below as a new variety.) 



A variety occurs in Texas with a few traces of plication in the sinus; and with one, two, 

 or three strong plications on the dorsal fold, or none at all; it approaches Huenella abnormis 

 (Walcott) in some of its extreme forms where the ribs are large on a prominent mesial fold. 

 In most young shells the sinus and fold are inconspicuous, the convexity is very moderate, 

 and the shell smooth; nearly all the characters of the adult are missing. 



