i8 



TABULATE CORALS. 



of a coenenchyma. The tabulse are always remarkably well 

 developed. Cohimnaria ? Halli, mild (the C. alvcolata of 

 American paleontologists), may be temporarily included in this 

 group, though there are grounds for believing that the walls of 

 its corallites are perforated, and its septa are of the marginal 

 character of Nyctopora Billingsii, Nich., which has unquestion- 

 able " mural pores," and must therefore be placed among the 

 Favositidiz. We may also provisionally place in or near the 

 CobunnariadcB the singular genus Lyopora, Nich. and Eth. jun., 

 though it differs from the typical Columnari(E in the great thick- 

 ness of its walls and the very rudimentary condition of its septa. 



As to the precise position of the typical ColumnaricB in the 

 zoological series, it does not seem at present possible to speak 

 with anything like certainty. The typical forms of the group 

 exhibit certain curiously Rugose features in the disposition of 

 the septa, and may really form a special type of the Rtigosa. 

 On the other hand, they present some conspicuous points of 

 resemblance to the Astrmdcs among the Zoantharia Aporosa. 



V. Syringoporid/E. — -In this group the corallum is fascicu- 

 late (figs. 5-7), commencing in the form of a creeping stolon- 

 iferous network, which sends up vertical and more or less 

 cylindrical corallites, which are never in absolute contact, ex- 



P^^y 



Fig. 5- — Syriii^opora rc/i~ 

 fonnis. Silurian. 



Fig. 6. — Syrini;opora ver- 

 ticillata. Silurian. 



Fig. ']. — Syrj)i«-opora Dal- 

 iiiani. Silurian. 



cept, perhaps, at quite limited intervals, and are enclosed by 

 strong compact walls. The visceral chambers of contio-uous 



o 



corallites are placed in direct communication by means of 

 hollow connecting-processes. Septa, of a spiniform and rudi- 

 mentary character, are present as a rule. The tabula; are 

 well developed, more or less funnel-shaped, and sometimes 



