16 NEW rOKK STATE MUSEUM 



making an annular segment, varying but little in widtii; their extremi- 

 ties are almost concealed beneath the projecting lobes in front. Occi- 

 pital furrow deep; occipital segment long and very much arched; no 

 central spine or tubercle. Cheeks with steep lateral slopes; somewhat 

 concave within the thickened margin. Furrows beneath the eyes deep, 

 narrow, with elevated margin having a vertical, outward slope. Occi- 

 pital furrow widening from the dorsal furrows outward and coming to 

 a rather abrupt termination without meeting the submarginal depression 

 of the cheek or extending on the genal expansion. Eyes large, ele- 

 vated, the palpebrum higher than the palpebral lobe. 



The thickened border bears a row of crenulations or crescentic orna- 

 mental processes, which are the most extended at the anterior extrem- 

 ity; here also the anterior three of these processes are somewhat coal- 

 esced. From this extremity may be counted, on both sides of the ter- 

 minal process, from 12 to 15 similar processes, becoming uniformly 

 smaller toward the genal extremities and finally disappearing altogether 

 at or near the lateral termination of the facial suture. In small speci- 

 mens the number of these processes may be considerably less. 



The surface of the cephalon is ornamented, on the frontal lobe of 

 the glabella, with coarse pustules of varying size ; this lobe also bears 

 the elongate median scar which occurs in many species of the genus. 

 The coalesced second and third lobes are also pustulose but less strongly. 

 The cheeks directly beneath the eyes bear traces of low ramifying 

 grooves similar to those found in Dal. pleuroptyx of the Helder- 

 bergian fauna and Dal. anchiops of the Schoharie grit. 



Thorax not observed. 



Pygidium very broadly triangular, the length and width being as 2 to 

 3. The margin curves slightly outward on each side and terminates behind 

 in a broad, rounded extremity which is slightly elongated but is not 

 produced into a spine. The axis bears 10 or 11 annulations, and the 

 pleurae 9 or 10. The ribs are undivided by a median groove and are 

 without coarse tubercles. 



Observations. This interesting species shows its immediate affinities 

 in many of its structural features. The peculiar ornamentation of the 



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