No. 1797. 



NEW TUBULIPOROID BRY0Z0A—BAS8LER. 



511 



work. The identity of the American form with Vine's species has 

 been determined by the study of an authentic example from the 

 original Wenlock shales material studied by Vine. A few zooecia of 

 this example are shown in figure 9a, and comparison of this with the 

 remaining figures of the American form indicates the specific identity. 

 The long stoloniferous processes mentioned by Vine as intermingling 

 with the cells are the stolons of ctenostomatous bryozoans such as 

 Vinella or Ascodidyon, having no connection at all, of course, with 

 Corynotrypa. Such widely diverse incrusting species are often found 

 with their zoaria intermingled, but it usually requires little care to 

 determine that one is merely growing over the other. The following 

 description brings out the characters of C. elongata as observed in the 

 present study. 



" ^ a . 



b d 



Fig. 9.— Cokynoteypa elongata. a, sketch of an authentic 

 SPECIMEN, X9. Silurian (Wenlock), England; 6, outline 



VIEW, X9, OF an AMERICAN EXAMPLE INCRUSTING THE EPITHECAL 

 SIDE OF A BRYOZOAN ; C, TWO ZOCECIA OF THE SAME, X20. SILU- 

 RIAN, ROCHESTER SHALE, ROCHESTER, NEW YORK. (f, PORTION 

 OF A ZOARIUM, Xl2, INCRUSTING A BRACHIOPOD. SILURIAN, WaL- 

 DRON SHALES. WaLDRON, INDIANA. 



Zoarium incrusting 

 foreign objects, the 

 smooth epitheca of 

 corals or bryozoans 

 being most frequent- 

 ly selected in the 

 American examples. 

 Zooecia uniserial, 

 branching at irregu- 

 lar intervals, slender, 

 fusiform, increasing 

 slowly in size from a 

 diameter of 0.03 mm. 

 to 0.04 mm. at the 

 proximal end, to one 



of 0.15 mm. to 0.18 mm. at the distal or anterior end, which, although 

 normally rounded, is sometimes slightly drawn out. An average zooe- 

 cium is 0.60 mm. in length; when arranged in a straight line, seven 

 zooecia may be counted in the space of 4 mm. ; angle of divergence 

 about 25°. Aperture small, rounded, subterminal, with a slightly ele- 

 vated border and less than half the greatest width of the zocecium in 

 diameter. Surface of the zooecia smooth, probably finely porous. 



Oorynotrypa elongata is most certainly the Silurian representative 

 of the abundant Ordovician C. delicatula, from which it differs mainly 

 in its increased angle of divergence. 



Occurrence. — Somewhat rare in the Buildwas beds of the Wenlock 

 shales, Sliropsliire, England; Clinton formation. Seven Mle Creek, 

 near Eaton, Ohio; Rochester shale, Rochester and Lockport, New 

 York; Waldron shale, Newsom, Tennessee, and Waldron, Indiana. 



Plesiotypes.—C&t. nos. 35475, 57107, U.S.N.M. 



