560 CAMBEIAN BRACHIOPODA. 



LiNGULELLA (LiNGULEPIS ?) sp. Unclt. (Walcott). 



Obolus (Lingulepis) sp. undt. Walcott, 1906, Proc. U. S. Nat. Mus., vol. 30, pp. 567-568. (Characterized as below 

 as an undetermined species.) 



This species is represented by a few fragments, one of which shows that the ventral valve 

 is elongate, and the apex acuminate. The shell was built up of several layers or lamellae, as 

 in characteristic forms of Lingulella {Lingulepis). The interior surface of some of the lamellae 

 is marked by fine, radiating, and concentric striae; the outer surface, under a strong magnifier, 

 shows fine, concentric, somewhat irregular striae. 



Formation and locality. — Middle Cambrian: (C72) Thin green-gray limestone interbedded with ocherous and 

 green clay shales, overlying the massive oolite in the Kichou formation [Willis and Blackwelder, 1907, pp. 139 and 

 145 (3d list of fossils)], 4 miles (6.4 km.) east of Fanglanchon, Shansi, China. 



Genus DELGADELLA Walcott.o 



Delgadella Walcott, 1908, Smithsonian Misc. Coll., vol. 53, Ko. 4, PL XI, and pp. 142 and 144. (Classification of 

 ■■) 



The description of the type species includes aU that is known of this genus. The form 

 of the shell is more like that of Lower Ordovician species referred to Lingula than to the typical 

 forms of Lingulella or Lingulepis. 



Type. — Lingulepis lusitanica Delgado. 



The generic name is given in memory of the late Mr. J. F. Nery Delgado, of the Geological 

 Survey of Portugal. 



Delgadella lusitanica (Delgado). 



Plate XXIX, figures 5, 5a-b. 



Lingulepis lusitanica Delgado, 1904, Communicagoes Commissao Servi?o Geologico Portugal, tome 5, fasc. 2, pp. 

 365-366, PI. IV, figs. 31-34. (Characterized and discussed in French as a new species. Photographs of the 

 specimens represented by figs. 31, 32, and 34 are reproduced in this monograph, PI. XXIX, figs. 5a, 5b, and 5, 

 respectively, each individual figure being a reversed view of Delgado's original figure.) 



General form elongate ovate, moderately convex. The greatest width of the ventral 

 valve is at the anterior third, whence the outline narrows slightly to the broadly rounded front, 

 and gradually to the subacuminate posterior half. 



Dorsal valve unlcnown, unless Plate IV, figure 17, and possibly figure 27, of Delgado, 

 represents it. However, these two shells are referred in this monograph to Lingulella delgadoi 

 (p. 491) as they appear to be more closely related to that species than to Delgadella lusitanica. 



Shell thick and with a thick margin. This is shown by the casts of the edges of the valves, 

 as shown by figures 5 and 5a. Shell substance unknown. Delgado [1904, p. 365] states that 

 the shells range from 5 to 8.5 mm. in length. 



Observations. — Delgado referred this species to Lingulepis on account of its general form, 

 but from the fact that it has a tliick, strong shell and does not have the attenuated extension 

 of the apex of the ventral valve of the typical forms of Lingulepis I am inclined to refer it to 

 a new genus characterized by a thick shell, spatulate form, with a subacuminate beak. A 

 shell agreeing with tliis in outline and form occurs in the Lower Ordovician shales at Kelleys 

 Island, Conception Bay, Newfoundland. 



Delgado [1904, p. 365] compares tliis species with the very young shells of Lingula lesueuri 

 Rouault [Davidson, 1866, PI. I, figs. 1-11]. If the specimens representing it had been sent 

 to me without any information as to the associated fauna, I should have been strongly inclined 

 to refer them to a Lower Ordovician fauna. 



Lingulella (Lingulepis) acuminata meelci (Walcott) has a somewhat similar outline, but 

 that is a thin, corneous sheU of the Upper Cambrian fauna. We must await further discov- 

 eries of more perfectly preserved material before a more complete description can be given. 



o Prior to the definition of the genus Delgaiella the type species was described under Lingulepis [Delgado, 1904, p. 365]. 



