EAKLY PALEOZOIC BEYOZOA OP THE BALTIC PROVINCES. 181 



MONTICULIPORA DAGOENSIS, new species. 



Text fig. 94. 



Zoarium a small, incrusting mass with a smooth, celluliferous 

 surface bearing inconspicuous maculae. The type-specimen is about 

 a centimeter in diameter and a millimeter thick, and is growing upon 

 a species of Heliolites. The surface presents no unusual features 

 unless it is slightly etched with acid and then examined, when moist- 

 ened, with a hand lens, when distinct acanthopores may be seen at 

 many of the junction angles of the zooecia. Such a view also shows 

 large and somewhat numerous mesopores as well as the cut edges of 

 the cystiphragms which appear in the zocecial tubes as circular or 

 semicircular lines. The apertures are small, polygonal, thin-walled, 

 with six in 2 mm., and, on the average, 0.23 mm. in diameter. The 





^l)(j2< 



Fig. 94.— Monticulipoea dagoensis. a, tangential section, X20, illusteating the distinct acan- 



THOPOEES AND OTHEE EEATUEES OP THE SPECIES; 6, POETION OF SAME, X35, SHOWING IN ADDITION THE 

 GEANTJLOSE WALL STEUCTUEE; C, VEETICAL SECTION, X20, THEOUGH THE MATUEE EEGION OF THE ZOA- 

 EIUM, EXHIBITING CLOSELY TABULATED MESOPOEES AND ZOCECIA WITH A DOXJBLE EOW OF CYSTIPHBAGMS. 

 LTCKHOLM LIMESTONE (Fl), KEETEL, ISLAND OF DAGO. 



mesopores are unusually large, sometimes almost equaling the 

 zocBcia from which they can always be distinguished by their lack of 

 cystiphragms. In addition to the structure described, a tangential 

 section brings out the peculiar granulose wall structure characteristic 

 of the genus. 



The incrusting growth, small, angular, thin-walled zocecia, large, 

 numerous mesopores and well marked acanthopores, are characters 

 of the present species which wUl separate it from all described forms 

 of the genus. 



Occurrence. — Rare in the Lyckholm limestone (Fl) at Kertel, 

 island of Dago, Baltic Sea. 



Holotype.—C&t. No. 57270, U.S.N.M. 



British Museum, thin section of the type-specimen. 



Genus ORBIGNYELLA Ulrieh and Bassler. 



Orhignyella Ulrich and Bassler, Smitlis. Misc. Coll., vol. 47, 1904, p. 18. — 

 Bassler, Bull. 292, U. S. Geol. Surv., 1906, p. 26. 



This genus was proposed for Monticuliporidse which differ from 

 Monticulipora in wanting its irregularly granulose wall structure, 



