» 



KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 32. N:0 I. 43 



tubed Heliolites with crenulated calicinal margin and twelve well developed septa reaching 

 nearly to the centre has the same name. In his Lethtea geognostica, last edition, pl. 9 

 fig. 3a, he has copied the figure of Hel. interstinctus of M. Edw. and at last in the 

 Lethaäa erratica», pl. v fig. 7, there is a new form without septa and nearly related to 

 the first mentioned. Not one of these, which represent at least thi'ee different species, 

 can be regarded as identical with Linn^.us' type and must be removed from the list of 

 the synonyms of Hel. interstinctus. We must not be led astray by the circumstance that 

 LiNNJEUS in subsequent editions introduced foreign and recent corals under the same 

 specific name. There exists indeed none besides the fossil Gotland form, which is to be 

 described below, to which the words »poris majoribus crenatis» and »marginibus aliquan- 

 tum crenato, crenis circiter duodecim» can be applied. 



In »Obersilurische Fauna des Timan» Herr N. Lebedeff^ has at p. 13 described a 

 coral, which he calls Hel. interstincta. But the description is so incomplete that the 

 identity must be doubted. Lebedeff's figures" on pl. i fig. 3 do not show the real 

 characters. 



Hel. interstincta Weissermel 1894 Korallen .... Preussens, p. 666 cannot be a true 

 interstinctus as he tells about »Zwölf wohl entwickelte Septen». 



As very doubtful forms of this species I regard the following. 



Porpital Madreporite, Pakkinsox. Org. remains II, p. 69, tab. vii f. 2, 4, 5. 



Sarcinula punctata, Fleming. Hist. of Brit. Aniraals p. 508. 



Porites favus Barrande MS from Tachlowitz. 



Hel. subtubulata, M'Coy. Palasoz. Foss. p. 16 pl. iC f. 2. 



Geoporites intermedia, D'Oebigny. Pi"odr. I, p. 49, according to M. Edw. & H. 

 identical with this species, but as D'Orbign'y does not give any characteristics, I cannot 

 find if he is right. 



Geoporites araericana, D'Orb. Prodrome p. 108 much uncertain = Hel. parvistella 

 F. Roemer ?. 



Hel. megastoma, Eichwald. Lethiea rossica I,i p. 453. 



Hel. interstincta, Nicholson & Etheridge. Girvan p. 57. 



A so common and so widely spread coral as Hel. interstinctus must already a priori 

 be expected to offer a great number of variations and mutations. And so it in reality 

 turns out to be. But in all this variability there is something in common and this will 

 serve to establish the specific description. 



The form of the polypary. As a rule the polypary has grown in flat or slightly 

 vaulted disks, in undulating placentoid pieces, plane or a little excavate below. A local variety 

 from the stratum d along the shore of Wisby, there very common, forms compressed, 

 broad branches bearing calicles on all sides. From the edges and the surface there project 

 finger- or hornlike prolongations, which when detached or broken might be mistaken for 

 independant polyparies. There are also irregularly globular or pjanform polyparies, but by 

 far not so common as the others. 



^ Mémoires du Comité géologique (de Russie) vol. xii, N:o 2. 1892. 



" There is in the explanation of the figures a coiifusion of the numhers, giving f. 3 for Propora tubu- 

 lata and f. 4 for Hel. interstinctus instead of vice versa. 



