170 



CCELENTERATA. 



[aca.- \i.\. 



Family Staurograptid^:. — Staurograptus. 



Family Thamnograptid^. — Bythograptus, Thamnograptus. 



Family Uncertain. — Dawson ia. 



Acanthograptus, Spencer, 1878, Can. Nat., 



vol.8,p.462. 

 [Ety. akan- 

 tha, spine ; 

 grapho, I 

 write.] 

 Shrub-like ; 

 one side 



Fig. 128.— Acanthograptus 

 pulcher. 



spinous. 

 Stronger 

 and more 

 bushy than 

 Dendro- 

 graptus . 

 Type A. 

 granti. 

 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 - 

 tabula? little de- 

 veloped; in- 

 creasing by 

 ge mmatio n. 

 Type A. bal- 

 tica. 

 adjunctive, 

 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.— Acervolaria 

 clintonensis. 



Fig. 130.— Acervularia davldsoni. 



davidsoni, Edwards & Haime, 1851, Pol. 

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

 Ham. Gr. 



inequalis, Hall & Whitiicl.l. l s7:s. 23d Rep. 

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

 mung Gr. 



pentagona, Goldfuss, 1826, (Cyathophyl- 

 lum pentagonum,) Petref. Germ., i». 80, 

 Devonian. 



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

 477, Ham. Gr. 



Acrophyllum, Thomson a Nicholson, 

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

 vol. 17, p. 455. [Ety. akro$, summit ; 

 phyllon, leaf.] Corallum simple, tur- 

 binate, or sub-cylindrical, straight, or 

 curved; septa numerous, well-dc\tl- 

 oped, coalescing, and curving as tin y 

 reach the tabulae, 

 forming promi- 

 nent, tortuous 

 ridges on the cen- 

 tral, elevated por- 

 tion, and becom- 

 ing complicated 'A ,»ft^ -*£>..! 

 with the tabula; f\ J ^S^jgJS \ 

 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- 

 daense. 



oneidaense, Billings, 

 L869, (Olieiophyl- 

 lum oneidaense, 

 Can. Jour., p. 128, 

 Up. Held. Gr. 



agaricia, Lamarck, 

 1801, Syst. des 

 Anim. sans Vert. 

 Not Palaeozoic. 



twinderniana, see Thecia swinderniana. 

 Alveolites, 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., vol 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. 



Pig. 181/— Acrophyl- 

 lum oneidaense. 



