40 



BULLETIN 64, UNITED STATES NATIONAL MUSEUM. 



the ridges, mostly horizontal but a few transverse, with which the surface of the plates 

 is ornamented. 



One of the columnar joints which is circular and large, is yet attached to the cavity, 

 but the alimentary canal [lumen] is completely rilled with siliceous matter and conse- 

 quently obliterated. 



The ornamental ridges on the scapulars fradials] are very regular and exactly repre- 

 sented in the figure. 



It was discovered by Prof. ,T. M. Safford * * * to whom I have dedicated the 

 species. 



Observations. — As will be seen by a comparison of the figures, the 

 specimen substituted by Hall for the type of this species is less than 

 half the size of Troost's type, and it differs in the character of the 

 surface ornament. On Troost's type many of the nodes become 

 confluent, producing ridges parallel to the margins of the plates, so 

 that while lines of nodes are present running from the angles of the 

 plates, parallel ridges form a more characteristic feature of the orna- 

 ment. Hall's specimen is probably a young individual of the species. 



Formation and locality. — Upper Burlington and Keokuk group. 

 Scottsville, Kentucky. Reported also from Indian Creek, Mont- 

 gomery County, Indiana; Keokuk, Iowa; Tennessee, Illinois, and 

 Missouri. 



Cat. No. 39890, U.S.N.M. 



PLATYCRINUS INSCULPTUS Troost. 



Plate 4, fig. 18. 



Platycrinites insculptus Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 1850, 



p. 62 (nomen nudum); MSS., 1850. 

 Platycrinus insculptus Shumard, Trans. Acad. Sci. St. Louis, II, No. 2, 1866, p. 



388 (catalogue name). — Wachsmtjth and Springer, Rev. Palseocrinoidea, II, 



1881, p. 234 (catalogue name).— Miller, North Amer. Geol. and Pal., 1889, 



p. 271 (catalogue name). 



The description by Troost is as follows : 



Of this species I possess only a pelvis [base]. It is distinguished from the preceding 

 species which are smooth by its engraved surface. The elevated circle around the 

 alimentary aperture [lumen] is also broader, has a more or less triangular form and 

 from each of the angles projects a little ridge. The remainder of the pelvis is adorned 

 first by a row of tubercles running along the margin, then five rows running from each 

 of the angles of the pentagonal pelvis to the circle around the alimentary aperture 

 [lumen]. 



Cumberland Mountains, Tennessee and Alabama. 



Observations. — This species is described from the basal plates only 

 and it is quite possible that it belongs to some already described 

 species, but as the specimen is missing, it is impossible from the 

 figure alone to place it with any degree of certainty. Since the 

 name has already appeared in the literature it seems best to publish 

 such evidence as exists concerning it, and await the collection of 

 more complete material from the same localities. 



