OLENELLUS AND OTHER GENERA OF MESONACID.E 



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CALLAVIA BICENSIS, new species 



Plate 41, Figs. 9, 9 a 



Cephalon longitudinally, broadly semi-elliptical ; strongly convex, 

 with the eye lobes and front lobe of the glabella rising abruptly 

 from the cheeks ; marginal border slightly rounded and separated 

 from the cheeks by a shallow, rounded groove ; it broadens somewhat 

 at the genal angles, where it is prolonged into spines ; the posterior 

 marginal border is narrow and convex beside the occipital ring, 

 from whence it flattens out and broadens before uniting with the 

 border at the genal angle ; an oblique thickening occurs where the 

 low ridge extending from the posterior end of the eye crosses the 

 margin. 



Glabella with a large, convex anterior lobe that rises abruptly from 

 the narrow space between .it and the anterior marginal border ; this 

 lobe has two short and slightly defined furrows on each side that 

 originate near the front margin of the palpebral ridge ; the posterior 

 of the two furrows extends inward on a line almost directly across 

 the lobe and the anterior furrow extends inward subparallel to the 

 rounded lateral margin of the lobe ; a narrow, low ridge extends 

 all about the front of the lobe very much in the same manner as a 

 similar ridge in CaUavia crosbyi [pi. 28, fig. i] ; the posterior lateral 

 angles of the lobe are connected to the palpebral lobe by a strong, 

 rounded ridge ; the second glabellar lobe is narrow and arched 

 slightly backward at each end so as to nearly enclose the ends of 

 the third lobe, which is thus shortened, but it is still transversely 

 longer than the fourth lobe ; the fourth lobe is transversely shorter 

 than the second and third, also a little wider ; the second, third, and 

 fourth lobes all arch backward, and are very faintly defined across 

 the center of the glabella. The glabella is narrow at the base, ex- 

 panding to where it unites with the palpebral lobe, from whence 

 it contracts toward its front margin ; this gives an outline some- 

 what similar to that of CaUavia hroggcri [pi. 27, fig. i]. Occipital 

 ring about the same width and Jength as the fourth glabellar lobe : 

 it is marked by a small median node that rises from its highest point 

 at the posterior margin. Palpebral lobes narrow, elevated, and 

 gently arched from their connection to the first glabellar lobe to 

 opposite the glabellar furrow between the occipital ring and fourth 

 glabellar lobe ; the posterior end of the lobe is about as far from the 

 side of the glabella as the width of the fourth glabellar lobe ; the 

 palpebral lobes, although elevated, do not rise to the level of the 

 4— w 



