BRACHIOPODA. 



[WOR. 



lata, Hall, 1881, (Fenestella lata,) Trans. 

 Alb. Inst., vol. 10, p. 34, and Pal. N. Y., 

 vol. 6, p. 136, Up. Held. Gr. 



nana, Hall, 1887, Pal. N. Y., vol. 6, p. 

 133, Up. Held. Gr. 



nervia, Hall, 1874, (Fenestella nervia,) 

 26th Rep. N. Y. St. Mus. Nat. Hist., p. 

 93, Low. Held. Gr. 



nervia var. constricta, Hall, 1879, (Fen- 

 estella nervia var. constricta,) 32d Rep. 

 N. Y. St. Mus. Nat. Hist., p. 174, Low. 

 Held. Gr. 



precursor, Hall, 1874, (Fenestella pre- 

 cursor,) 26th Rep. N. Y. St. Mus. Nat. 

 Hist,, p. 94, Low. Held. Gr. 



pernodosjj, Hall, 1881, (Fenestella perno- 



), p. 

 Held. Gn 



dosa,) Trans. Alb. Inst., vol. 10,' p. 35, 

 Pal. N. Y,, vol. 6, p. 139, Up. Held. Gr. 

 projecta, Hall, 1887, Pal. N. Y., vol. 7, p. 



132, Up. Held. Gr. 

 retrorsa, Ulrich, 1886, Cont. to Am. Pal., 



p. 15, Up. Held. Gr. 

 scalaris, Hall, 1884, (Fenestella scalaris,) 



36th Rep. N. Y. St. Mus. Nat. Hist,, p. 



66, Ham. Gr. 

 spatiosa, Hall, syn. for U. lata. 



stipata, Hall, 1881, (Fenestella stipata,) 

 Trans. Alb. Inst., vol. 10, p. 34, and 

 Pal. N. Y., vol. 6, p. 134, Up. Held. Gr. 



tegulata, Hall, 1881, (Fenestella tegulata,) 

 Trans. Alb. Inst., vol. 10, p. 34, and 

 Pal. N. Y., vol. 6, p. 135, Up. Held. Gr. 



trans versa, Hall, 1887, Pal. N. Y., vol. 7, 



p. 132, Up. Held. Gr. 



WORTHENOPORA, Ulrich, (in press,) Geo. 

 Sur. 111., vol. 8, p. 403. [Ety. proper 

 name.] Bifoliate, branching or pal- 

 mate; cells regularly arranged, subtu- 

 bular or elongate rhomboidal, with the 

 aperture semi-elliptical; on the surface 

 the line of junction between the cells is 

 marked by an elevated ridge ; the 

 truncated posterior margin of the aper- 

 ture is raised into a less strong trans- 

 verse bar ; the elongate triangular de- 

 pressed front appears perfectly plane. 

 Type W. spinosa. 



spatulata, Prout, 1859, (Flustraspatulata,) 

 Trans. St. Louis Acad. Sci., vol. 1, p. 

 446, Warsaw Gr. 



spinosa, Ulrich, (in press,) Geo. Sur. 111., 

 vol. 8, pi. 68, Keokuk and Warsaw Grs. 



SUBKINGDOM MOLLUSCA. 



CLASS BRACHIOPODA. 



[Ety. brachium, arm ; pous, foot.] 



THE Brachiopoda are all marine animals, having a bivalve shell and a pair of 

 long, ciliated, and usually spiral arms, with which they produce a current of water 

 that carries the food to the mouth, which is close to the middle of the base of the 

 shell. The valves of the shell, instead of being placed on each side of the animal, 

 as in the Lamellibranchiata, are placed above and below it ; so they are dorsal and 

 ventral valves, instead of right and left valves. The ventral valve is generally 

 larger than the dorsal, and projects beyond it at the beak. The beak is generally 

 perforated, for the passage of a muscular peduncle, for the attachment of the ani- 

 mal ; but in the Lingulidse, the peduncle projects from the interior of the shell, 

 between the umbones. When there is no peduncle, the shell attaches by the beak, 

 or by the whole surface of the ventral valve. The dorsal valve is always free and 

 imperforate. There is generally a pair of teeth in the ventral valve, developed 

 from the hinge margin, that lock in corresponding cavities in the dorsal valve. 

 Some genera have no teeth or hinge. 



The shells of the living Rhychonellidse and of many fossil genera consist of 

 flattened prisms, parallel with each other, and directed obliquely to the surface of 

 the shells, the interior of which is imbricated by their outcrop. The substance of 



