13 



side than directly in front of the glabella, there being at this place a gently 

 convex elevation resembling that which occurs in Barrande's species, O. 

 Sulzcri and C. coronatus. The ocular ridge is well defined where the 

 surface is preserved, but is rarely visible in the sandstone casts. Most of 

 the specimens are distinctly carinate along the median line of the glabella. 



It is possible that there may be a median tubercle on the neck segment, 

 but none of our specimens have this part sufficiently well preserved to 

 shew it. 



The following are the dimensions of a specimen of the average size : 

 Length of head 5 lines ; length of glabella 3i lines ; greatest width of 

 glabella 2 lines ; width of glabella at front 1J line ; distance of eye from 

 side of glabella 2 lines. 



Dedicated to Prof. C. B. ADAMS, late State Geologist of Vermont. 



Locality and Formation. Highgate, Vermont, in the Potsdam group, 

 about a mile east of the Highgate Springs. 



Collectors. Rev. J. B. Perry, Dr. G. M. Hall, and E. Billings. 



CONOCEPHALITES TEUCER, (N. Sp.) ? 

 Fig. 16. 



Compare C. Billingsi, (Shumard.) SUliman's Am.. Jour, of Science. 2d Series, 

 vol. 32, p. 220. Sept. 1861. 



Description. Head semi-oval ; glabella conical, convex, well defined all 

 round by the dorsal furrows, about two-thirds the whole length of the 

 head, widest just in advance of the neck furrow, sides gently convex, front 

 neatly rounded, neck furrow well defined all across ; posterior furrows 

 commencing at about one-half the length of the glabella, and running 

 inwards and backwards nearly to the neck furrow and one-third across ; 

 median furrows curved backwards, and extending one-fourth across ; an- 

 terior furrows short ; ocular ridges well defined ; front margin one-third 

 the whole length of head, with a well defined groove running across, in 

 front of which there is an elevated marginal rim, which rises with a flat 

 slope upwards and forwards ; the groove across the margin is situated at 

 about one-fourth the distance from the front of the glabella to the elevated 

 edge of the rostrum ; the cheeks are moderately tumid ; the neck segment 

 is well developed, with a small median tubercle scarcely the fourth of a 

 line in he%ht, and in some specimens seems to be absent altogether. 



Thorax of 13 or 14 segments ; axis strongly defined, cylindrical ; side 

 lobes about one4hird wider than the axis. 



The pygidium is very small, being, scarcely one-sixth the length of the 

 thorax. The only specimen in which it has been observed attached to the 



