No. 1797. 



NEW TUBULIPOROID BRY0Z0A—BAS8LER. 



509 



Miller applied the name Stomaiopora proutana to the very elongate 

 form from the Corryville bed at Cincinnati, while specimens with the 

 same characters but coming from the lower part of the Eden shale 

 were described as S. tenuissima by Ulrich. The form with short 

 zooecia was named Rhopalonaria pertenuis by Ulrich, but later placed 

 by him as a synonym of S. proutana Miller. Nickles and Bassler 

 recognized James's name, but considered S. tenuissima of sufficient 

 value to rank as a variety. The present study indicates that this 

 last form has the zooecium typical of the species and differs only in 

 its greatly elongated stolon. 



Occurrence. — ^An abundant fossil, beginning with the Stones 

 River, in practically all of the Middle and Upper Ordovician and 

 earliest Silurian (Richmond) formations of North America. In 

 Europe the species is less abundantly represented, but is known 

 from several of the Middle Ordovician formations of the Baltic 

 provinces of Russia. 



Plesioty pes. —Cat. nos. 13615, 43260, 43263, 54156, 54165, 54199, 

 U.S.N.M. 



CORYNOTRYPA BARBERI, new species. 



At first sight this new species seems to be only an exceptionally 

 large form of C. delicatula, but upon closer inspection other differ- 

 ences may be noted. These are, especially, the rapid swelling of 



Fig. 8. — CORTNOTRTPA BARBERI. a, PORTION OF THE TYPE-SPECIMEN, X9, INCRUSTING A BIFOLIATE 



brtozoan; 6, SEVERAL zocecia, X20. Ordovician, Ottosee formation, Knoxville, Tennessee. 



C, PART of a small COLONY, X9, GROWING UPON' A SPECIES OF HeLIOLITES. EaRLY SILURIAN, 



Lyckholm formation, Hohenholm, Island of Dago, Baltic Sea. 



the zooecia after the stolonal portion has been left behind, and the 

 marked difference between the stolon and the zooecium proper. In 

 C. delicatula the angle of divergence is so small (15°) and the increase 

 in the zooecial diameter so gradual that it is difficult to discriminate 



