204 TABULATE CORALS. 



while as the single representative of the family of the Haly- 

 sitidce, while Syringopora must be considered as the type of a 

 new family, for which the name of Syringoporidcz may be ap- 

 propriately chosen. The only other form which can, in the 

 meanwhile, be at all definitely placed in the Syringoporida is 

 Cannapora, Hall. The few specimens which I possess of this 

 singular genus which, so far as is known, is confined to the 

 Upper Silurian deposits of North America are so poorly pre- 

 served that I have been unable to make microscopic sections of 

 them, and can give no details as to their minute internal struc- 

 ture. Dr Rominger (Foss. Cor. of Michigan, p. 85, 1876) has, 

 however, examined good specimens of Cannapora jnnciformis, 

 Hall, the type-species of the genus, and the following generic 

 diagnosis is given by him : 



" Colonies of closely-approximated erect tubules, with stout 

 walls, sprouting from an incrusting basal expansion, formed of 

 prostrate tubules, growing and multiplying in the same manner 

 as an Aulopora. The erect ends of the tubules are annulated 

 by wrinkles of growth and by sharp-edged periodical offsets 

 marking an interruption and renewed growth from the inner 

 circumference of the old orifices. The sides of the tubes are 

 partly connected by horizontal expansions of the walls, partly 

 in direct contiguity, in which latter case the otherwise circular 

 tubes are pressed into a polygonal shape, and connect in the 

 contiguous parts by lateral pores. The orifices are slightly 

 dilated at the margins, radiated by twelve spinulose projections, 

 rows of which extend through the whole length of the tubes. 

 Diaphragms are not often developed, direct, transverse, and not 

 funnel-shaped as in Syringopora" 



From the above description it will be evident that Cannapora 

 supplies us with a very interesting link between Syringopora 

 and Favosites, though upon the whole most closely allied to the 

 former. Cannapora closely resembles Syringopora in its habit 

 and general form, and the periodically-produced horizontal 

 expansions which connect contiguous corallites have been shown 

 by Rominger to be sometimes developed in Syringopora tabii- 



