120 NEW YORK STATE MUSEUM 



Calymmene senaria Conrad 

 PL 9, fig. 6-10 



The Canajoharie shale in the Mohawk valley often contains as one 

 of its more frequent fossils quite large specimens of Calym- 

 mene senaria. These, as first noticed by Doctor Ulrich, bear 

 upon the occipital ring a larger median tubercle not found in the 

 common Trenton or Utica specimens and obviously representing a 

 varietal character. It is distinctly seen on the specimen reproduced 

 in figure 6, but the largest specimen here figured also possessed a 

 larger, though flatter elevation upon the middle of the occipital ring. 



The material of this species from the Canajoharie shale proved 

 especially interesting through the fact that the fine black shale has 

 retained the earlier growth stages. Among the latter was found a 

 well-preserved specimen of a protaspis (see plate 9, figure 7), 

 which to our knowledge has not as yet been observed of this genus. 

 The very prominent marginal eyes and the fine segments of the 

 glabella, the middlemost of which is largest, are the most striking 

 features of this trilobite embryo. We also figure a nepionic and 

 early neanic stage to illustrate the changes in the glabella, leading 

 to the suppression of the embryonic annulations. The protaspis 

 here figured is practically identical with that referred to P r e t u s 

 parviusculus by Beecher,^ and the question arises 

 whether it should not also be referred to that genus. Since our 

 protaspis is fairly well connected with the adult Calymmene by 

 the neanic stages here figured, and Proetus parviusculus 

 has not been found associated with it in the Canajoharie beds; we 

 feel certain of its ontogenetic connection with the common 

 Calymmene senaria of that formation. 



Ulrichia ? bivertex Ulrich 



PI. 9, fig. II, 12 



Associated with Primitiella unicornis the Cana-^ 

 joharie shale at Canajoharie contains in considerable numbers an' 

 ostracod of rather striking appearance through two prominent tuber- 

 cles near the dorsal margin. This species was first published by 

 Doctor Ulrich as Leperditia bivertex (title 8, page 10) 

 from the neighborhood of Cincinnati and is now referred by him to 



^The larval stages of Trilobites. Amer. Geologist 16, pi. 9, figs; 5, 6. 



