KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 32. N:0 I. 53 



authors and Fistulipora according to Nicholson.^ The chief differences in structure which 

 make it irnpossible to see aflänities between the Heliolitida^ and the above mentioned 

 genera may here be enumerated. 



1. Amongst the Heliolitid» we do not find the least traces of acanthopores so 

 significant to palteozoic bryozoa. 



2. There are on the surface of the Heliolitidse never any »maculse» nor »monticuli». 



3. Their calicular apertures are never closed by false »opercula». 



4. The intimate microscopical structure is in both groups dissimilar. In the 

 Heliolitidaj it agrees with that which is seen in most recent or fossil corals, consisting 

 of diminutiva fibrillse, which are directed upwards from their starting point, while 

 those of the bryozoa are directed downwards. See numerous instances in the works of 

 NicHOLSON, Dybowski and others where sections of bryoza are given. 



5. In the bryozoans there have never been discovered the least traces of any structure 

 at all to be regarded as homologous with septa. In Dybowskiella (= Lichenalia) for iu- 

 stance, which according to Waagen, is a true coral and nearly related to Heliolites, he 

 States that there are two septa. ^ But these so called septa are nothing else but the 

 »lunarium» or »lunula» so characteristic for many both pateozoic, mesozoic and probably 

 also recent bryozoa. This structure occuvs in the palasozoic genera Lichenalia (= Dybow- 

 skiella), Fistulipora, Coscinium, Ceramoporella and many others, in the mesozoic (jurassic) 

 Chilopora, in Salicornia from the Oligocaäne formation, in Lepralia from the Crag and 

 recent seas. It is a crescentic plate or incrassation below the aperture of the zoocEcium 

 formed by its peristome and of course of variable shape in the different genera, but all 

 homologous and referable to the same type. In some of the sections figured by Waagen 

 it seems to have been detached from the peristome lying loose beside it and has probably 

 been altered through pressure in the rock. 



6. The bryozoa have no coenenchyma in the same sense as Heliolites and the 

 interspace or tubes between the zoooecia are now considered as absorbed zoooecia and 

 termed mesopores. There are also »intravesicular tissues». Waagen has not given decisive 

 proof that what he calls coenenchymal gemmation in Dybowskiella proceeds in the same 

 manner as in Heliolites. 



7. There is a decided dissimilarity between the interiör structure of the bryozoa 

 and the Heliolitidfe, many of the former having imperfect diaphragms, and they are 

 provided with the characteristic cystophragms. 



Heliolites porosus. Goldfuss. 



Pl. II figs. 29—37. Pl. III figs. 3—7. 



1770. Héliolithe pynforme GUETTARD. Mémoires sur différentes parties des Sciences et des Arts, vol. 2 p. 429 



pl. 22 f. 13 — 14, vol. 3 p. 454. Speciraens from Eifel. He considers Madrep. 

 intevstincta of LlNN^US as identical. 



^ Tabulate Corals pl. xv, f. 3a. 



^ Palseont. Indica, Foss. Productus-limestone xiil, p. 917 etc, pl. Cil, fig. 3. 



K. Sv. Vet. Akad. Haudl. Band 32. N:o 1. 



