56 



BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



brachiopod shells. Although all three are in a fair state of preserva- 

 tion, they add no new features to the original description given above. 

 Vinella repens is a characteristic Black River fossil in America, 

 and the occurrence of such typical examples of the species in the 

 same general horizon in Russia is only another instance of the strati- 

 graphic value of these delicate biyozoans. The fine radiating threads 

 of this species are so different from any other associated bryozoan 

 that comparisons are unnecessary. Usually the preservation is by 



Fig. 5.— Vinella repens. a, two colonies, natural size, attached to the inner side of a ventral 

 VALVE or Strophomena septata; &, portion of one of the colonies, X18. The pores are absent, 



PROBABLY not HAVING BEEN PRESERATED; C, ANOTHER PORTION OF SAME ZOARIUM, X18, SHOWING A 

 NUCLEUS WITH FIVE DIVISIONS OF THE TUBULAR STOLON RADIATING FROM IT. THIS PORTION OF THE 

 SPECIMEN ALSO PRESERVES SOME OF THE PORES MARKING THE POINTS WHERE THE ZOCECIA WERE ATTACHED; 

 d, ANOTHER SPECIMEN, NATURAL SIZE, ATTACHED TO A FRAGMENT OF SHELL; e, SMALL PORTION OF SAME, 

 X18, WITH THREE TUBES LYING PARALLEL WITH EACH OTHER. THE LONGITUDINAL LINES ARE STRONGER 

 THAN USUAL. PHYLLOPORINA BED OF BLACK RiVER (DECORAH) SHALES AT ST. PAUL, MINNESOTA. 



(After Ulrich.) 



the black iron pyrites, which gives a clue in the identification of poor 

 specimens. 



Occurrence. — Not uncommon in the Phylloporina bed of the Black 

 River (Decorah) shales in Minnesota. Less common in the Jewe 

 Umestone (Dl) at Baron Toll's estate (Cat. No. 57507, U.S.N.M.), 

 and in the Wesenberg limestone (E) at Wesenberg, Esthonia (Cat. 

 No. 57179, U.S.N.M.). 



Typical American specimens of this species are in the collections of 

 the British Museum. 



