278 



BULLETIN 77, UNITED STATES NATIONAL MUSEUM. 



In the size of its zooBcia alone this species is so decidedly ' different 

 from other ramose Trepostomata that comparisons are unnecessary. 

 The specific name is in honor of the late Dr. August von Mickwitz, 

 who collected the type-specimens. 



Occurrence. — Common in tiie Wassalem beds (D3) at Uxnorm, 

 Esthonia. 



Cotypes.—€ait. No. 57380, U.S.N.M. 



Thin sections of the type-specimens and two specimens from the 

 type locality are in the collections of the British Museum. 



BATOSTOMA WINCHELLI (Ulrich). 



Text fig. 166. 



Amplexopora xoinchelli Ulrich, Fourteentli Ann. Rep. Geol. Nat. Hist. Surv. 



Minnesota, 1886, p. 91. 

 Batostoma winchelli Ulrich, Geol. and Nat. Hist. Surv. Minnesota, vol. 3, pt. 1, 



1893, p. 295, pi. 26, figs. 33-37; pi. 27, figs. 1-6.— Simpson, Fourteenth Ann. 



Rep. State Geologist of New York for the year 1894, 1897, p. 588, fig. 174. 



Fig. 166. — Batostoma -wtnchelli. a and b, two fragments op natueal size; c, sueface of a, X9 



AND XlS; d, TANGENTIAL SECTION, X18, SHOWING CHARACTER OF A MATURE EXAMPLE; e, SMALL POR- 

 TION OF A TANGENTIAL SECTION OF A YOUNG SPECIMEN, X18; /, SEVERAL ZOCECIA OF FIGURE d, X50; 

 g, VERTICAL SECTION, X18, OF AN ORDINARY SPECIMEN. BLACK RlVER (DECORAH) SHALE, St. PAUL, 



Minnesota. (After Ulrich.) 



The Russian specimens referred to this abundant American species 

 show external and internal features so similar to those figured below 



that the illustrations of the American form will serve for both, 

 following are the essential characters of the species: 



The 



