524 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 39. 



A series of specimens from tlie Silurian rocks of various localities 

 in Europe and America shows that the Wenlock shales species 

 described by Vine as Stomatoyora dissimilis has as wide a geographic 

 distribution as certain Ordovician species of Corynotrypa. As indi- 

 cated in the above synonymy, the American form was figured by 

 Hall in 1852 without a specific designation, and later was figured and 

 described by Ringueberg as Stomatopora recta. 



The zoarium of C. dissimilis is parasitic, other bryozoans, brachio- 

 pods, and crinoid columns or plates being usually selected; uniserial, 

 with lateral series branching usually irregularly, but sometimes very 

 regularly and at right angles to the main series, as shown in figure 24. 

 Zooecia subcylindrical rather than club-shaped, about 0.10 mm. in 

 diameter at the proximal end and increasing to 0.35 mm. at the 



rounded distal portion; an average 

 zooecium is 1.15 mm. in length. Aper- 

 tures large, subterminal, slightly ex- 

 sert. Zooecia marked transversely by 

 fine wrinkles or striations. 



The large zooecia with their trans- 

 verse striations or wrinkles particu- 

 larly characterize C. dissimilis and 

 serve to distinguish it from all other 

 Paleozoic species of the genus. The 

 relations of the species to Stomatopora 

 have been discussed in the remarks 

 upon the C. dissimilis section (p. 522). 

 Occurrence. — The earliest appear- 

 ance of C. dissimilis is in the Lyck- 

 holm limestone of Baltic Russia, in 

 strata equivalent to the Richmond 

 group of America. These specimens 

 (see figs. 23c and d) differ only in lacking the transversely wrinkled 

 surface, a condition due probably to their somewhat imperfect 

 preservation. The types are from the Buildwas beds of the Wenlock 

 shales, Shropshire, England. The species occurs also in the Silurian 

 beds. Island of Gotland, where it has been given the name Stomatopora 

 .minor by Hennig. It is abundant in the Rochester shale at Lockport 

 and other localities in western New York, and at Grimsby, Ontario, 

 and in the Osgood beds at Osgood, Indiana. 

 Plesiotypes.— Cat. nos. 35473, 57112, U.S.N.M. 



CORYNOTRYPA TENNESSEENSIS, new species. 



The two well-preserved specimens upon which this new species is 

 based present a combination of characters so similar to those of 

 C. dissimilis that the same description, with slight emendations, will 



Fig. 24.— Corynotrypa dissimilis. a and 



6, PORTIONS OF A ZOARIUM, X9, PARASITIC 

 UPON A FRAGMENT OF A SpIRIFER. SILU- 

 RIAN, Rochester shale, Lockport, 

 New York. This specimen illus- 

 trates BRANCHING AT RIGHT ANGLES. 



