26 



G. LINDSTRÖM, HEHOUTID.T;. 



luay, however, not he laid oii tlic t(jtal abseiice of all fonnectiiia; liuks betAveRii these 

 genera tVoni tlie eiid of the middle Devoniaii to thc Receiit times. 



Several fossil corals have been called Heliopora, whicli on closer iuspectioii by no 

 nieans can be cousidered as sncb. Milne Edwakds and Haime referred to Heliopora two 

 species from the Cretaoeous strata of Gosau, which Reuss had described as belonging to 

 liis genus Polyti'einacis. Tliey had better to be left there, as may be found by studying 

 the bealitifnl figures of ReuösJ Whatever they may be, they are certainly no Heliopora^. 

 The same is the case witli Heliop. detbrmis Michelin, which fossildealers send under that 

 name frotn the tertiaries of Auvers in France. Quenstedt^ has described and tigured a 

 Heliopora bipartita fi'om Berchtesgaden. From the figures to judge he has commingled 

 two difierent species, none of them a Heliopora. In one (hg. 14) the two opposite septa 

 of the tirst order, (because they must be genuine septa), have coalesced with a little colu- 

 mella in the centrum. The other form, Heliop. var. sparsipora (fig. 19), differs so com- 

 })Ietely that it must be assumed it belongs to another genus than the former. If there now 

 is no evidence of fossil Heliopora Ave have to take the recent Hel. coerulea into considera- 

 tion as the only species known. 



Several authors, as Hinde, Neumayr, Wentzel etc, have already denied all alliance 

 between Heliopora and Heliolites. 



As Neumayr has well pointed out there are no true septa. The short, blunt spines, 

 which surround the edge of the calicle, are nothing else but the same sort of echinula- 

 tions which stånd up on the coenenchyma between its open tubes and are only continua- 

 tions from the core or nucleus, the string which forms the centre of the j'ods, that make 

 up the whole of the corallum. This central string which evidently is the oldest part of 

 the rod, as it grows in advance of the ambient tegument, is of a splendid cream colour, 

 which by transmitted light looks black. It is enclosed by a mäss of påle, blue-greenish 

 calcite fibrilte, growing out from it upwards in an acute angle. These rods meet from 

 opposite sides around the calicles and the coenenchymal tubes and at the meeting-point 

 they have a jagged outline. A feature in Heliopora, which decidedly removes it far 

 from the Heliolitidte is the total want of a calicular theca. The pseudosepta or rather 

 the tubercles around its rim are not in any way connected with each other, nor do they 

 grow out from any theca as in the Heliolitidse. 



There is no gi-ound for the statement that the calicles of Heliopora as a rule are 

 surrounded by twelve such pseudosepta, as in Heliolites. In one and twenty calicles I 

 found the nuraber of the pseudosepta to be as shown in the annexed table. 



Number of calicles . . . 

 Number of septa in each 



2 

 10 



2 

 11 



2 

 12 



4 

 13 



3 



14 



5 

 15 



1 



16 



2 

 17 



As BouKNE remarked before me fifteen seems to be the most prevalent number. 



1 Denkschriften der K. K. Akad. der Wissenschaft. vol. VII, pl. 24. — Zittel Palseozool. 1, p. 212 

 also has given figures of »Heliopora» Polytremacis Partschi partly copied from Rbuss and partly (f. 122 a) new, 

 differing from the figures of the latter . especially as to the coenenchyma. The longitudinal section clearly shows 

 the difference from Heliopora. 



^ Petrcfact. Deutschlands p. 164, pl. 149 fig. 14—19. 



