Öfversigt af Kongl. Vetenskaps-Akademieus Förhandlingar 1900. N:o 1. 

 Stockholm. 



On Thecocyathus Nathorsti n. sp., a Neocomian coral 

 from King Charles Land. 



By G. Lindström. 



Presented to the R. Swe^ish Academy of Sciences January lOth 1900. 



It is remarkable how very few species of Turbinolian corals 

 occur in the strata of the mesozoic formations in comparison 

 with the great number of composite colonies of other families 

 "which are derived froni thera. Every new contribution, however 

 small it may be, to the knowledge of that interesting group 

 which is so richly represented in the tertiary, and also in recent 

 times, may therefore be welcome. 1 have consequently thought 

 it worth the while to give a notice of two small specimens of 

 Turbinolians, brought home in 1898 by Prof. A. G. Nathorst, 

 who found them, during his arctic expedition of that year, in 

 King Charles Land, situated east of Spitzbergen, No other 

 corals but these were found there. The strata, in which they 

 were enclosed, belong, according to the determination of Dr. J. F. 

 POMPBCKJ, ^) to the Neocomian stage of the Cretaceous formation. 



These tiny corals are of a turbinate shape having the out- 

 side transversally, finely wiinkled or even grooved through irregular- 

 ity in growth. It is difficult to decide whether this covering is 

 to be called epitheca or theca, as there is not in a horizontal 

 section the least distinction between two such structures. There 

 is only the incrassated, homogenous theca enclosing the septa 



') Marines Mesozoicum von König Carls Land, in »Ofveisigt af Vetensk. Akad. 

 Förhand!. 1899, p. 462—463. 



