CRUSTACEA. 265 



Surface bearing tubercles which are closely disposed over the frontal lobes, but are 

 scattered or obsolescent on the lateral lobes. On the posterior slope of the frontal lobe 

 these tubercles appear to be arranged in two longitudinal rows of three or four each. 



The spines of the head shield are covered with acute pustules and granules " 



Hal!, 1888. 



Remarks — A fragmentary glabella corresponds with the descriptions and illustra- 

 tions of this species as shown in the New York Palaeontology. 



Horizon — Upper beds. 



Figured specimen No. 27543, Walker Museum. 



Order Proparia 



Family Phacopidae 



Genus Dalmanites Barrande 



Dalmanites cf. aspinosus Weller 



Plate 71, figures 10, 11 



1905. Dalmanites aspinosus Weller, Pal. N. J., vol. 3, p. 252, pi. 22, fig. 15. 

 1913. Dalmanites aspinosus Maynard, Geol. Surv., Md. Low. Dev., p. 499, pi. 91, fig. 

 16. 



Description — Three incomplete pygidia comprise the only material available for 

 study. The dimensions of the largest specimen are approximately: Length 18 mm., 

 width 26 to 27 mm. Semi-elliptical in outline, posterior pointed. Axis only partly 

 preserved, tapering uniformily, and reaching to within 2 mm. from the posterior margin; 

 the portion preserved divided into 10 annulations which posteriorly become obscure. 

 Lateral lobes with 8 curved pleural, angular and prominent, oblique to the lateral 

 margins; shallow grooves separate the pleura. 



Remarks — With such inadequate material the identification of these specimens with 

 Dalmanites aspinosus Weller, is uncertain, but the sharp angular pleural ribs extending 

 to the lateral margins of the pygidium, and the absence of any marginal border, strongly 

 suggest this species. From the incomplete pygidia neither the number of pleural ribs, 

 nor the axial annulations can be certainly determined. In size the specimens are com- 

 parable to those from the Maryland Oriskany. Those from New Jersey as figured by 

 Weller are considerably larger. 



Honzon — Lower beds. 



Figured specimens No. 27541, Walker Museum. 



Dalmanites cf. bisignatus Clarke 



Plate 71, figure 12 



1903. Dalmajutes bisignatus Clarke, Mem. N. Y. State Mus., vol. 3, No. 3, p. 19, pi. 2, 

 figs. 6-8. 



Description — Pygidium distinctly triangular, length greater than width, pleural 

 lobes sloping steeply to the lateral margins; posterior margin apparently extended into 

 a flattened spine. Axis convex, tapering, sides straight or slightly concave; portion 

 preserved divided into 12 segments. Lateral lobes strongly convex, with 14 segments, 

 separated by broad, flat grooves. Ribs flat, well defined to lateral margin and divided 

 longitudinally by fine median depressions. No marginal border present. Surface 

 ornamentation indistinct, consisting of a few, nearly obsolete pustules on the axial 

 portion. 



Remarks — This form is represented by a single imperfect pygidium which hardly 

 merits specific determination. It resembles Dalmanites bisignatus as figured by Clarke 



