Contributions to Palceontology. 195 



third across the glabella ; occipital furrow and wel noarwr 

 defined; occipital ring wider, more prominent in the 

 middle, and produced into a node (which in the crust 

 has probably been a short spine). Dorsal furrow well 

 defined, and continuing of the same width and strength 

 in front. Fixed cheeks a little wider at base, prominent 

 and continuing in a convex border in front. 



The specimens have the form and aspect of Arionellus hipuncta- 

 tus; but the glabella is more distinctly lobed, and the puncta at 

 the anterior angles do not exist in this one. 



CONOCEPHALITES OPTATUS ( n. s.). 



Specimens retaining the glabella and fixed cheeks have been 

 observed. 



Glabella narrow conical, and rounded anteriorly. The 

 posterior lobe is small, oblique, and nearly separated 

 from the glabella : the middle lobe is oblique, and longer 

 than the posterior one; anterior lobe less distinct. 

 Occipital furrow narrow and well defined: occipital 

 ring rounded, prominent, and a little more elevated than 

 the summit of the glabella. 



The glabella slopes to a broad depression in the frontal limb, 

 which is terminated by an abruptly elevated border. The posterior 

 limb of the fixed cheek is much extended laterally ; and the facial 

 suture approaches the glabella near the front, where the fixed cheek 

 preserves a little elevated ridge like a palpebral lobe. 



This species is interesting in perserving the peculiar characterise 

 tics of the Genus Conocephalites, and also approaching the C. 

 sulzeri of Europe. 



