CRUSTACEA 41 



posterolateral spines, (b) the lateral margin is not spinose, (c) the termination 

 of the axis is connected by an angular ridge with the margin. 



Distribution. Upper Helderberg group. Schoharie grit, Schoharie, Schoharie 

 count v. 



[s.-g.] CRYPH.EUS, Green. 1837. 



Dalmanites (Cryph.eus) comis, n sp. 



PLATE XVI \, FIG. 1. 



A small and somewhat incomplete pygidium indicates an undescribed species 

 of this sub-genus. It is characterized by the narrow axis curving slightly 

 inward on the margins, and bearing six annulations, four distinct and elevated, 

 and the last two faintly defined. The pleurae are moderately broad, sloping 

 somewhat abruptly toward the margins, and bear five annulations, each of 

 which terminates in a short, blunt spinule, with the apex directed backward. 

 Whether or not there was a terminal spinule, as in the other American species, 

 cannot be determined from this specimen. The pygidium has a length of 

 4 mm. and a width of 5 mm. 



Distribution. In the decomposed chert of the Corniferous limestone, Walpole, 

 Province of Ontario. 



Dalmanites (Cryphjeus) Pleione. 



PLATE XVI A, FIG. J. 



Dalmania Pleione, Hall. Descr. New Species of Fossils, etc., p. 62. 1861. 



Dalmania Pleione, Hall. Fifteenth Rept. N. Y. State Cab Nat, Hist., p. 90. 1862. 



Dalmanites Pleione., Hall. Illustrations of Devonian Fossils, pi. xvi. tig. 17. 1876. 



CryphCBUs Pleione, Kav.-ek, Abhandl. z. Geol. Specialkavte von Preussen, etc . Band ii, Heft I. p 33. IsTs 



The imperfect pygidium which served as the original of this species is closely 

 similar in general proportions, number of annulations and marginal spines to that 

 of D. Booihi var. Calliteles. The spines however are relatively longer, more slen- 

 der, rounder and more distant than in the mature individuals of the variety 

 mentioned, but have a striking similarity to the pygidia of the young of that 

 form. Our knowledge of the species in America is at present limited to the 



