INTRODUCTION. Ixi 



but much shorter, and terminated by an oblique semicircular or subtriangular calice. the- 

 edge of which projects on one side. 



Typ. sp., Alveolites spongites, Steininger, Mem. de la Soc. Geol. de France, vol. i ; Caluvw/jura 

 spongites, Goldfuss, Petref. Germ., pi. xxviii, figs. 1", l 4 , l c . 



Second Tribe— CHyETETINvE. 

 Corallum massive. Walls not perforated. Neither septa nor ccenenchyma. 



5. Genus Ch^etetes. 



Fischer, Oryct. du Gouv. de Moscou, p. 159, 183". 



Corallum glomerate. Coraflites very long, basaltiform, and in general more or less 

 bent. Calices polygonal. Tabula independent, not connected in the adjoining corallites:. 

 nor placed on the same level throughout the corallum. 



Typ. sp., Chcetetes radians, Fischer, loc. cit., pi. xxxvi, fig. G. 



6. Genus Dania. 



Milne Edw. and J. Haime, Comptes rend., t. xxix, p. 261, 1849. 



Corallum having most of the characters of Chsetetes, but with the tabulae connected 

 through the different corallites so as to constitute a series of common plates, and to divide 

 the whole mass into a great number of parallel strata. 



Typ. sp., Dania Huronica, Milne Edw. and J. Haime, loc. cit. 



7. Genus Stenopora. 



(Pars) Lonsdale, Geol. of Russia and Ural Mount., vol. i, p. 631, 1845. 



Corallum very similar to Chsetetes, but having small styliform processes at the angles 

 of the calices. 



Typ. sp., Stenopora spinigera, Lonsdale, loc. cit., pi. a, fig. 2. 



8. Genus Constellaria. 

 Dana, Zooph., p. 537, 1846. 



Third Tribe— HALYSITIN/E. 



Corallum composed of corallites constituting vertical lamina? or fasciculi, but more or 

 less free laterally, and united by means of connecting tubes or mural expansions. Walls 

 well developed, and not porous. Septa distinct, but small. 



