EAELY PALEOZOIC BEYOZOA OF THE BALTIC PROVINCES. 167 



value could be found between these Borkholm specimens and those 

 from the Niagaran in America. 



Numerous epithecated bryozoans from various localities have been 

 registered as Lichenalia concentrica, because Hall's description and 



Fig. 84.— Lichenalia concenteica. a, epithecal side of a feagmentaet specimen. Boekholm 



LIMESTONE, BOEKHOLM, ESTHONIA ; 6, POETION OF A TANGENTIAL SECTION, X20, CUTTING THE HIGH 

 ANTEEIOE end of the PEEISTOME and A FEW OF THE CONNECTING TTALLS; C, A TANGENTLA.L SECTION, 

 X20, PASSING THEOUGH A LOWEE POETION OF THE ZOAEIUM THAN IN C. ThE LOWEE POETION OF THE 

 FIGUEE ILLUSTRATES THE ZOCECIA AND MESOPOEE-LIKE STEUCTUEE OF THE MATURE EEGION, THE MIDDLE 

 POETION, THE OBLONG OE EECTANGULAE SHAPE OF THE ZOCECIA IN THE IMMATURE ZONE, WHILE IN THE 

 UPPEE PAET OF THE DEAWING AEE SHOWN POETIONS OF THE CONCENTEIC EINGS OF THE EPITHECA; d, A 

 TANGENTIAL SECTION, X6, PASSING CLOSE TO THE SUEFACE OF THE ZOAEIUM AND CUTTING ONE OF THE 

 MEANDEEING CANALS; €, A POETION OF A TANGENTIAL SECTION, X20, ILLUSTRATING THE NATURE OF THE 

 WALLS OF THE MESOPOEE SPACES; /, A VEETICAL SECTION, X20,ILLUSTEATINGTHE FOLLOWING CHAEACTEES: 

 Z, THE ZOCECIA; C, ONE OF THE CANALS, COVEEED ABOVE; ub, UNDULATING BASE OF ZOAEIUM; W , WALLS 

 FOEMING THE MESOPOEE-LIKE SPACES; p, THE E5TEEMELT HIGH POSTERIOR PORTION OF THE PERISTOME; 

 a, THE LOW ANTEEIOE PORTION OF THE PERISTOME; AND p' , A POSTEEIOE POETION OF THE PEEISTOME 

 CUT obliquely; g, a MOEE DIAGEAMMATIC VEETICAL section, X20, SHOWING ESPECLALLY THE LOW AND 

 HIGH POETIONS OF THE PEEISTOME AND THE WALLS OF THE INTEEZOCECLA.L SPACES. ROCHESTER SHALE, 



LocKPOET, New Yoek. (After Basslee.) 



figures applied only to the basal portion of these subcircular expan- 

 sions and gave no idea at all of the surface or internal characters. 

 More detailed characters of the genus were not published until 1906/ 



I Bull. 292, U. S. Geol. Surv., 1906. 



