3'4 PALEONTOLOGY 



mural pores perforating the thecae; Pachypora (Dev.), 

 similar but branching, with thickened walls; Alveolites 

 (Sil.-Dev.), similar to the last, but calyces cuspate- 

 triangular; Michelinia (Carb.), with tabulae strongly 

 arched, corallum with thick epitheca bearing root-like 

 out-growths ; Syringopora (Sil.-Carb., Fig. 94, /), coral- 

 lites cylindrical, spaced out and connected by horizontal 

 tubes, tabulae funnel-like; Aulopova (Sil.-Carb. j, an en- 

 crusting network of tubular corallites, with raised trumpet- 

 like apertures; Halysites (Ord.-Sil., Fig. 94, i), like the 

 last, but corallites rise up vertically, forming linear 

 series the "chain-coral"; Heliolites (Sil.-Dev., Fig. 

 94, h), massive, two kinds of corallites, abundant small 

 polygonal and scattered larger cylindrical, both with 

 tabulae, the latter with apparent septa. 



Short Bibliography. 



GRAPTOLITES. 



ELLES, G. L., WOOD, E. M. R., AND LAPWORTH, C. 

 British Graptolites, Palczontographical Society (1901-18). 



RUEDEMANN, R. Graptolites of New York, 2 vols. 

 New York State Museum (1904-08). 



MARR, J. E. AND NICHOLSON, H. A. Phylogeny of 

 Graptolites, Geol. Mag., dec. 4, vol. ii. (1895). 



HOLM, G. On Didymograpttis, Tetragraptus and Phyllo- 

 graptus, transl. Elles and Wood, Geol. Mag., dec. 4, 

 vol. ii. (1895). 



The first of the above-mentioned works contains a 

 detailed historical account and bibliography of the 

 Graptolites. 



STROMATOPOROIDS. 



NICHOLSON, H. A. British Stromatoporoids, Pal. 

 Soc., 1886-92. 



