212 TABULATE CORALS. 



The septa in Syringopora are usually, if not always, detected 

 without difficulty in thin sections, whether vertical or trans- 

 verse ; and their most striking feature is, that they are 

 thoroughly " Favositoid " in character, having the form of 

 slender spinules arranged in vertical rows (fig. 30). They 

 never extend more than a limited distance into the interior 

 of the visceral cavity, and they vary much in length. Not 

 uncommonly, also, the descending tabulae carry on their inner 

 faces slender spines (as in the Favositoid genus Chonostegites, 

 E. and H.), which seem to represent inward prolongations of 

 the septa. They are also variable in number, not unfrequently 

 exceeding twenty in a single cycle. Lastly, they are composed 

 of a sclerenchyma which is conspicuously lighter in tint than 

 that of the walls of the corallites (see PI. X., fig. 5). As the 

 result of this, long sections in parts where they happen to 

 coincide with the wall of a corallite (fig. 30, A) exhibit vertical 

 rows of rounded spaces of lighter colour than the surrounding 

 tissues, these being really the cut ends of the spiniform septa 

 divided near their bases, though they might at first sight be 

 readily mistaken for mural pores. 



With regard to the affinities and zoological position of 

 Syringopora, a consideration of the foregoing account of its 

 minute structure will, I think, render it clear that the genus 

 cannot be referred to the Halysitida, to the Tiibiporidce, or to 

 the Rugosa, one or other of these courses having been gener- 

 ally followed by palaeontologists. From Halysites, the genus 

 Syringopora is fundamentally separated by the general form of 

 the corallum, the entirely different construction of the tabulae, 

 the total absence of a set of small zooids coexisting with one 

 of larger dimensions, and the presence of hollow connecting- 

 processes placing the visceral chambers of contiguous corallites 



some forms from the Carboniferous Limestone of Russia appear to have the funnel- 

 shaped tabulae open inferiorly, whereas they are closed in Syringopora. So far as I 

 understand the ambiguous language which he uses on this point, the differences 

 alluded to by Ludwig are of no moment whatever ; and at any rate, the forms which 

 he describes as Harmodites are shown by his figures to be typical species of 

 Syringopora. 



