328 BULLETIN 77, UNITED STATES NATIONAL MUSEUM. 



HALLOPORA WESENBERGIANA (Dybowski). 



Plate 4, fig. 2-2h; text fig. 205. 



Monticulipora wesenhergiana Dybowski, Die Chaetetiden der Ostbaltisclien Silur- 

 Formation, 1877, p. 95, pi. 3, figs. 2a-'h. 



Dybowski records this as a very abundant species at Wesenberg 

 and gives a lengthy description and numerous figures of its charac- 



FiG. 204.— Hallopoea goodhuensis. a, tangential section, X20, of a small but well developed 

 RussL^N specimen; 6, vertical section of the same specimen, X20. Wassalem beds (P3), Uxnokm, 



ESTHONIA. 



ters. He fails to illustrate the tabulation, a most important char- 

 acter in the discrimination of such species, but I have no doubt that 

 the common Hallopora of the Wesenberg limestone, whose internal 

 characters are shown in figure 205 is Dybowski's Monticulipora wesen- 

 hergiana. 



Fig. 205.— Hallopoea wesenbeegiana. a, tangential region, X20, of tee outermost part of the 



MATURE zone; 6, TANGENTLVL SECTION, X20, CUTTING THE EARLY PORTION OF THE MATURE REGION 

 "WHERE MESOPOEES ARE BEST DEVELOPED; C, VERTICAL SECTION, X20, SHO"VnNG CHARACTERISTIC TABU- 

 LATION. AVesenbeeg limestone, Wesenberg, Esthonia. 



As shown in Dybowski's figure, the branches frequently and irregu- 

 larly divide and average 5 mm. in diameter. Their surface is smooth, 

 but maculae of larger zooecia and more numerous mesopores are fre- 



