EAELY PALEOZOIC BRYOZOA OP THE BALTIC PROVINCES. 255 



Occurrence. — Eichwald cites the species from the "calcaire a 

 Orthoceratite," at Pulkowa, Popowa, and Wesenberg. In the col- 

 lections before me it is present in the Echinospherites limestone (Cl) 

 at Reval (Cat. No. 57329, U.S.N.M.); in the Kuckers shale (C2) 

 at Erras (Cat. No. 57330, U.S.N.M.); the Jewe Ihnestone (Dl), 

 Baron Toll's estate (Cat. No. 57328, U.S.N.M.), Esthonia; and the 

 Chasmops limestone, south of Bodahamn, Oeland, Baltic Sea. 



Plesiotype.— Cat. No. 57328, U.S.N.M. 



British Museum, specimens from_ localities in Esthonia and from the 

 island of Oeland. 



ORBIPORA SOLIDA, new species. 



Text fig. 148. 



Zoarium of dome-shaped, hemispheric or elongated soUd masses 

 usually several centimeters in diameter and of corresponding height. 

 The type-specimen, which is one of the largest examples seen, is an 

 elongate oval mass about 40 mm. in diameter and 75 mm. in length. 

 Surface smooth, maculae as in the type-species being apparently 

 absent. Zocecia direct, polygonal and of equal size when fully 

 matured. Occasionally a young zooecium giving the appearance of a 

 mesopore is present, but true mesopores are wanting. Three to four 

 zooecia occur in 2 mm. Acanthopores numerous and conspicuous at 

 the junction angles of the zooecia. 



The internal structure is essentially the same as in Orhipora 

 distincta save that a few scattered diaphragms are occasionally 

 developed. The acanthopores, while not as numerous as in 0. 

 distincta, are larger and have very distinct central openings. 



The more massive zoarium, less abundant acanthopores, and par- 

 ticularly the smaller zooecia of the present species will readily dis- 

 tinguish it from the related form, 0. distincta. 



Occurrence. — Not uncommon in the Orthoceras limestone (B3) 

 island of Rogo, and at Reval and vicinity. 



Holotype.— Cat. No. 57331, U.S.N.M. 



British Museum, fragment and thin sections of the type-specimen, 

 and specimens from Reval, Esthonia. 



ORBIPORA ACANTHOPHORA, new species. 

 Text fig. 149. 



Zoarium a rounded mass about a centimeter in diameter, with a 

 small, flat basal portion covered with a wrinkled epitheca. Surface 

 without monticules or maculae, but hirsute on account of numerous 

 large acanthopores arising from the cell walls. Zooecial apertures 

 irregularly polygonal and much indented by the acanthopores; three 

 to four zooecia in 2 mm. Mesopores wanting; four to six acantho- 

 pores surround an aperture. 



