508 CAMBRIAN BRACHIOPODA. 



LiNGULELLA? INSONS (Bairande). 



Plate XXXII, figures 2, 2a-e. 



Lingula insons Barrande, 1879, SystSme silurien du centre de la Boheme, vol. 5, PL CV, figs, x: 1-6. (Not described, 

 but figured as a new species. PI. CV, figs, x: 4A, 3A, 5A, 6A, 6E, and If are copied in this monograph, PI. 

 XXXII, figs. 2, 2a-e, respectively.) 



This is one of the forms that, ia the character of the area of the ventral valve, suggests 

 both Lingulella and Lingula. It is iatroduced more to call the attention of students to the 

 type than as a representative of the genus Lingulella. It is possible that it niay belong to the 

 subgenus Leptemholon of Mickwitz. 



Formation and locality.— Lower Ordovician: (303d) Etage dl, at Swarow; and (303e) Etage dl at Sta. Benigna; 

 both [Barrande, 1879b, PI. CV] in Bohemia, Austria-Hungary. 



Lingulella iole (Billings). 



'^' Plate XXVII, figures 5, 5a. 



Lingula iole Billings, 1865, Geol. Survey Canada, Paleozoic Fossils, vol. 1, p. 215, figs. 199a-e. (Described as a new- 

 species. The two specimens represented by figs. 199a-e are redrawn in this monograph, PI. XXVII, figs. 5 

 and 5a.) 



The type specimens of this species sent to me by Prof. J. F. Wlriteaves included single speci- 

 mens of the ventral and dorsal valves showing only the outer surface, and, where that is exfo- 

 liated, the surface of the inner layers or lamellae.. The surface is marked by very fine concentric 

 striffi and lines of growth and very fine, obscure, radiatmg strise upon the outer surface which 

 are slightly more marked on the inner layers. The edges of the lamellae indicate that the shell 

 was of moderate tliickness, less so than that of Oholus cyane (Billings). The ventral valve has a 

 length of 7.5 mm.; width, 5 mm.; the dorsal valve is 6 mm. in length and 4.5 mm. in width. 



This species is associated with Oholus cyane and belongs to the same group of species, so far 

 as can be judged from the external form and appearance of the shell. 



The stratigraphic horizon appears to correspond with the upper portion of the Cliazy and 

 base of the Trenton, of the New York section. 



Formation and locality. — Lower Ordovician: (314d) Limestone ot Division P [Billings, 1865a, p. 215] of the 

 "Quebec group," 4 miles (6.4 km.) northeast of Portland Creek, Newfoundland. 



Lingulella irene (Billmgs). 



Plate XXVII, figures 6, 6a. 



Lingula irene Billings, 1862, Geol. Survey Canada, Paleozoic Fossils, vol. 1, pp. 71-72, figs. 64a-b. (Described as a 



new species. The specimens represented by figs. 64a-b are redrawn in this monograph, PL XXVII, figs. 6a 



and 6, respectively.) 

 Lingula irene Billings, 1863, Geol. Survey Canada, Fifteenth Kept. Progress, p. 230, figs. 240a-b. (No text reference. 



Figures copied from previous reference.) 

 Lingulella irene (Billings), Schuchbrt, 1897, Bull. U. S. Geol. Sm'vey No. 87, p. 257. (Merely changes generic 



reference.) 



General form subovate; broadly rounded in front with the ventral valve subacumtnate 

 and the dorsal valve rounded at the beak. Surface of shell marked by concentric lines and 

 striae of growth and fine radiating strise. The specimens are almost flattened in the shale and 

 the substance of the shell has been very largely removed, so that it is impossible to determine 

 the marldngs upon the surface, the layers of which it may have been formed, or its thickness. A 

 thickened rim on the ventral valve indicates that the shell was strong and probably built up as 

 in other species of Lingulella. The type specimen, the ventral valve, as compressed in the 

 shale, has a length of 16.5 mm., with a maximum width of 13.25 mm. The dorsal valve is 15.5 

 mm. in length and 14 mm. in width. 



The area of the ventral valve is strongly marked and relatively long. It is divided midway 

 by a clearly defined pedicle furrow and toward the lateral margins by shai-p flexure lines. Fine 



