544 NEW YORK STATE MUSEUM 



PLATE 27 



Glossograptus ciliatus Emmons 



See plate 26, figures 1-5 

 Page 379 



i Rhabdosome, showing both the straight and curved spines 



2 Portion of fragment, showing both sets of spines in superposition 



3 Rhabdosome, showing thecal apertures and inflation of nemacaulus 



4 Specimen showing the double, lateral spines of the apertures 



Normanskill shale, Glenmont, N. Y. 



Glossograptus ciliatus mut. horridus nov. 



See plate 26, figures 8, 9 

 Page 383 



5 Enlargement to show the three axes and the ledges of the periderm 



Graptolite shale, Summit, Nev. 



Glossograptus quadrimucronatus var. approximatus nov. 



See plate 26, figures 10-13 

 Page 392. 



6 Enlargement of portion of macerated rhabdosome to show the ledges 



and reticulate layer of the periderm 



7 Young synrhabdosome, showing central disk and siculae 



Utica shale, Dolgeville, N. Y. 



Glossograptus quadrimucronatus var. cornutus nov. 



Page 393 



8 Young rhabdosomes, showing the sicula and reflexed growth direction 



of first theca (cotype) 



9 Sicula with first theca (cotype) 



10 Sicular extremity of older rhabdosome, showing the relation of first 

 theca to lateral spine (cotype) 



Utica shale, Rural cemetery, Albany, N. Y. 



