182 



BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



and in having cystiphragms so poorly defined that they appear more 

 hke merely curved diaphragms. A third difference noted was in the 

 acanthopores, which, in Monticulipora, are imperfectly defined, 

 granulose spots, while in Orhignyella they are sharply defined, well- 

 developed structures, as in the Heterotrypidss, 



a 



mm «/ 



<* 



Fig. 95. — Orbigntella gekmana. a, the ttpe-specimen, natural size; h, view op the usual charac- 

 ters SEEN IN TANGENTUL SECTION, X20; C, TANGENTIAL SECTION, X20, SHOWING DEVELOPMENT OF ACAN- 

 THOPORES IN DIFFERENT STAGES OF THE ZOARIUM. THE STRUCTUTtE OF THE MOST MATURE ZONE IS SHOAVN 

 IN THE LOWER HALF OF THE FIGURE; d, PORTION OF THE SAME, X35, SHOWING MINUTE STRUCTURE IN 

 MORE detail; e, vertical SECTION, X20, WITH ACANTHOPORES LITTLE DEVELOPED; /, ANOTHER VERTICAL 

 SECTION, X20, SHOWING THE NUMEROUS DUPHRAGMS AND STRONG ACANTHOPORES OF THE MATURE 

 REGION (a) WITH A SHORT IMMATURE ZONE (6). WASSALEM BEDS (D3), UXNORM, ESTHONIA. 



Genotype. — Orhignyella suhlamellosa Ulrich and Bassler. Middle 

 Ordovician (Stones River) of Tennessee. 



ORHIGNYELLA GERMANA, new species. 



Text fig. 95. 



Cfr. Monticulipora lamellosa Ulrich, Geol. Surv. Illinois, vol. 8, 1890, p. 408, 

 pi. 32, figs. 4-4&. 



Zoarium a globular mass about 10 mm. in diameter and 15 mm. 

 in height; surface smooth, maculae inconspicuous and distinguishable 

 only by the presence of zooecia slightly larger than the ordinary. 



J 



