Explanations of Plates. 



Legend, f . funicle. 



c. . central disc. 

 g. gonangium. 

 pn. basal cyst. 

 Types of figures on Plates I-III from the Utica slate of Dolge- 

 viUe, ISr. Y. 



Plate I. 

 Fig. l.-^Diplograptus pristis, Hall. JS'atural size. 

 Fig. 2. — Diplograptus Euedemanni, Gurley. Natural size. 

 Fig. 3. — D. Ruedemanni^ Gurley. 



Gonangia preserved as pits. X 4. 

 Fig. 4. — D. BuedemoMni, Gurley. 



Central disc with inclosed funicle; part of the speci- 

 men represented on PL II, fig. 1. X 22. 

 Fig. 5. — D. pristis, Hall. X 4. 



g. — Gonangium, filled with siculae. 

 Si. — Sicula with two thecse. 

 Sg. — Khabdosome with discernible sicula. 

 Fig. 6. — D. Ruedemanni, Gurley. X 10. 

 f. — Inside of funicle. 

 c. — Inside of central disc. 

 Fig. 7. — D. Buedemanni^ Gurley. X 2. 

 The basal cyst is broken out. 



pn. — Impression of basal cyst. 

 Fig. S.—D.pristis^ Hall. X 3. 



Fig. 9.— i>. pristis, Hall. X 2. 

 Fig. 10. — D. Buedemanni, Gurley, X f . 

 Yiew of the under side. 



