170 



CCELENTERATA. 



[ACA. AI,V. 



FAMILY STAUKOGRAPTID^E. Staurograptus. 



FAMILY THAMNOGRAPTID^E. Bythograptus, Thamnograptus. 



FAMILY UNCERTAIN. Dawsonia. 



ACANTHOGRAPTUS, Spencer, 1878, Can. Nat., 

 vol. 8, p.462. 

 [Ety. akan- 

 tha, spine ; 

 grapho, I 

 w rite.] 

 Shrub'-like ; 

 one side 

 s p i nous. 

 Stronger 

 and more 

 bushy than 

 D e n dr o - 

 graptus. 

 Type A. 



FIG. 128. Acanthograptus 

 pulcher. 



a 



granti, Spen- 



cer, 1878, 



Can. Nat.,vol. 8, p. 463, and Bull. No. 1, 



Mus. Univ., St. Mo., p. 31, Niagara Gr. 

 pulcher, Spencer, 1884, Bull. No. 1, Mus. 



Univ. St. Mo., p. 32, Niagara Gr. 

 ACERVULARIA, Schweigger, 1820, Handb. der 



Naturg., p. 418. [Ety. acervus, a heap; 



considered as a body.] Compound, 



massive, cells presenting two separated 



walls, as in Aulophyllum; septa well 



developed between the walls, but much 



less in the central area ; no columella ; 



tabulse little de- 



v e 1 o p e d ; in- 



cr easing by 



gemmatio n. 



Type A. bal- 



tica. 

 adjunctiva, 



White, 1880, 



Proc. U. S. Nat. 



Mus., vol. 2, p. 



255, and Cont. 



to Pal. No. 6, p. 



120, Carbonif- 



erous. 

 clintonensis, Nicholson, 1875, Ohio Pal., 



vol. 2, p. 227, Niagara Gr. 



FIG. 129. Acervularia 

 clintoneusis. 



FIG. 130. Acervularia davldsoni. 



davidsoni, Edwards & Haime, 1851, Pol. 

 Foss. d. Terr. Pal., p. 418, Up. Held, and 

 Ham. Gr. 



inequalis, Hall & Whitfield, 1873, 23d Rep. 

 N. Y. St. Mus. Nat. Hist., p. 233, Che- 

 mung Gr. 



pentagons, Goldfuss, 1826, (Cyathophyl- 

 lum pentagon um,) Petref. Germ., p. 60, 

 Devonian. 



profunda, Hall, 1858, Geo. Sur. Iowa, p., 

 477, Ham. Gr. 



ACROPHYLLUM, Thomson & Nicholson, 

 1876, Ann. and Mag. Nat. Hist. 4th ser., 

 vol. 17, p. 455. [Ety. akros, summit ; 

 phyUon, leaf.] Corallum simple, tur- 

 binate, or sub-cylindrical, straight, or 

 curved; septa numerous, well-devel- 

 oped, coalescing, and curving as they 

 reach the tabulse, 

 forming promi- 

 nent, tortuous 

 ridges on the cen- 

 tral, elevated por- 

 tion, and becom- 

 ing complicated 

 with the tabulse 

 to form the con- 

 spicuous, central 

 prominence, 

 which often forms 

 a central axis ; 

 fossette reaches 

 from the base of 

 the elevation to 

 the margin of the 

 calyx ; exterior 

 usually constrict- 

 ed. TypeA.onei- 



FIG. 131. Acrophyl- 

 lum oneidaense. 



oneidaense, Billings, 

 1859, (Clieiophyl- 

 lum oneidaense, 

 Can. Jour., p. 128, 

 Up. Held. Gr. 



agaricia, Lamarck, 

 1801, Syst. des 

 Anim. sans Vert. 

 Not Palaeozoic. 



swinderniana, see Thecia swinderniana. 

 ALVKOLITES, Lamarck, 1801, Syst. des Anim. 

 sans Vert., p. 375. [Ety. alveus, cavity ; 

 lithos, stone.) Dendroid, massive, or in- 

 crusting; corallites short, prismatic, or 

 cylindrical ; walls united ; tabulae com- 

 plete ; mural pores large, usually near 

 the angles of the tubes, few in number ; 

 calices oblique, lower lip most promi- 

 nent ; septa absent, or forming tooth- 

 like projections. Type A. escharo- 

 ides. 



arctica, Woodward, 1879, Lond. Geo. Mag. 

 n. s., yol 5, Devonian. 



billingsi, Nicholson, 1874, Geo. Mag. n. s., 

 vol. 1, p. 55, Up. Held. Gr. 



confertus, Nicholson, 1874, Geo. Mag. 

 n. s., vol. 1, p. 54, Up. Held. Gr. 



