34 



Found in tlic Burlinj^ton Group, at Burlington, Iowa, and now iu 

 the collection of A. Albers. in whose honor we have i^roijosed the 

 specific name. 



STEGAXOCRINLS GHIFFITHI, n. Sp. 



Plate II, Fig. 17, nzygous side; Fitj. 18, opposile view; Fig. 19, 

 liti.'tal view; Fig. 20, summit view. 



Species small. Calyx obpj'ramidal, broadly truncati'd. i)i>ii(ai:onal 

 as seen from above or below. Plates nodose, pyramidal. 



Basals form a short, liexa^onal cup, deeply notcliod at the sutures. 

 First primary radiais large, nodose, pyramidal, wider than long, three 

 hexagonal, two heptagonal. Second primary radiais al)out half as 

 large as the first, wider than long, hexagonal. Third primary radiais 

 smaller than the second, pentagonal, axillary, and beyonii these i)lates 

 our specimen is not preserved. Ten ambulacral openings penetrate 

 the vault. 



Th(> interradial areas all graduate up into the vault and over the 

 ambulacral channels so as to leave no dividing line between the vault 

 and calyx. The first regular interradial is followed by two i)lates 

 that unite with two plates that belong to the vault and two that cover 

 part of the ambulacral canals. In the azygous area, the first plate is 

 in line with the first ])rimary radiais, but somewhat smaller. It is 

 followed by two plates in the second range and three in tlie thii'd that 

 unite with the plates of the vault and those covering part of the 

 ambulacral channels. 



The vault is only slightly convex and bears a central proboscis. 

 It is covered with rather large convex plates. 



This species most resembles S. sh(u-onetisis, from which it is dis- 

 tinguished by tlie character of the ornamentation, by the form of the 

 basal plates, and by having a less number of plates in the interradial 

 areas and upon tlu' \ault. 'I'lie vaults are so different that the two 

 species will not be taken for each other. 



Found in the Burlington (froui). at Burlington. Iowa, liy Dr. H. 

 Ct. (Trifhth. formerly of that jjlace. but now residing in Pliiladelphia. 

 We take pleasure in dedicating this species to the learned doctor and 

 naturalist wlio discovered it. It is now in the collection of Mr. A. 

 Albers. 



