NO. 1395. CAMBRIAN BRACHIOPODA—WALCOTT. 255 



marked charactei's of the dorsal valve is the hirge transverse space — 

 pseiidocruraliuni — beneath the umbo. In one example it is crossed ver- 

 tically by the main vascular sinuses. What may be a trace of a low, 

 simple, rounded cardinal process is shown in one cast. The crura were 

 strong, with small dental sockets beside them. 



X. {J. ) perpasta resembles Nisuxki alherta in form and convexity, 

 but it does not have a spinose surface. 



Formation and locality.— \jO\iQY Cambrian. Quartzitic sandstone 

 of the "Skrejband." Kamenna hurka near Tejfovic; also Skrej 

 (Slapnicky) Bohemia. 



NISUSIA (JAMESELLA) PERPASTA MACRA Pompeckj. 



Orihis perpasta macra Pompeck.f, Jahrbuch k. k. geoly^eichsanstalt, XLV, 1896, 

 p. 516, pi. XV, fig. 14. y^ 



Original description. — Some internal toasts and iijtpressions of dorsal valves agree in 

 outline perfectly with the dorsal valves of OrtJiis perpasta, but differ from the type 

 form by much less arching and ribs farther apart. 

 Occurs in the same localities as Orthis perpasta. 



Oh.^crvatkms. — The gradual increase in the width of the interspaces 

 between the ribs, from a very narrow space to several times the width 

 of the rib, makes this variety of doubtful value. 



NISUSIA (JAMESELLA) PERPASTA SUBQUADRATA Pompeckj. 



Orthis perpasta var. subquadrata Pompeck.i, Jahrbuch k. k. geol. Reichsanstalt, 

 XLV, 1896, p. 516, pi. xv, figs. 19, 20. 



Original description. — As compared with the type form, this variety is distinguished 

 by less breadth, the length being to the breadth as 3 to 4. The anterior angles of 

 the straight hinge edge are drawn in somewhat more than in Orthis perpasta f. typ. 

 The ventral valve is higher, with higher and steep area, pierced by a large triangular 

 foramen. The sinus, which extends from the high vertical apex to the frontal edge, 

 is bordered by obtusely rounded edges. Dorsal valve proportionally more bulged 

 than in the type form. Sculpture as in Orthis perpasta i. typ. 



The outer form strikingly recalls Orthisinae; but the pseudodeltidium, the median 

 septum, and the spondylium of the ventral valve are lacking. 



Orthis perpasta var. subquadrata was found in several internal casts and impressions, 

 together with Orthis perpasta f. typ., more rarely in greywacke sandstone than in 

 the conglomerate-like, quartzitic sandstone. 



Obser'oations. — This variety apparently is not constant, as ventral 

 valves occur in the material before me that have the subquadrate form 

 with relatively less convexity than the convex forms of the species 

 per])a8ta. 



NISUSIA (JAMESELLA) UTAHENSIS, new species. 



Ventral valve transverse, strongly convex; most elevated at the 

 umbo, which is surmounted by the upward pointing apex at the edge 

 of the area; area slightly inclined forward from the hinge line; delthy- 

 rium large and covered by a convex deltidium. Surface marked by 



