Contributions to Palceontology. 



127 



tures. The posterier glabellar furrows are sometimes 

 continued in a slight depression across the centre. The 

 frontal limb is sometimes, but not always, a little pro- 

 duced in the middle, and a shallow furrow is always 

 perceptible. 



A well-formed specimen gives the following measure- 

 ments : Length of glabella, 0-30 of an inch; width at base, 

 0-29 ; width at apex, 0-22 ; frontal limb, 0-12 ; entire 

 length of head, 0-48. 



A pygidium in the same association, and apparently belonging to 

 this species, has the anterior margin much curved, the axis very 

 prominent, and the lateral lobes convex near the axis, concave and 

 flattened towards the margins. The axis is marked by four annula- 

 tions, exclusive of the anterior ridge : the posterior one is elongate, 

 and apparently indented about the middle of its length. The lateral 

 lobes have three or four ribs, which are longitudinally divided, and 

 terminate in a flattened border : the divisions are narrow and promi- 

 nent. 



In species like this one, it is not easy to point out the characters 

 which separate them from such forms as Dikelocephalus spiniger or D. 

 pepinensis ; and we have the features of glabella intermediate 

 between the more characteristic forms of Conocephalites and 

 Dikelocephalus. In this one the glabella is more conical, and 

 the posterior glabellar furrows scarcely united across the summit. 



The pygidium which occurs in several specimens associated with 

 the glabella, has the prominent axis and broad lateral lobes with 

 wide margin which are characteristic of the Dikelocephalus, and 

 I am therefore induced to place the species under that genus. 



This species occurs in the second fossiliferous beds at Trempaleau, 

 and in the greenish sandstone near the same horizon at Miniska, 

 about the middle of the formation. 



