242 Systematic Paleontology 



broken specimen as a new species. Its greatly elongate, narrow form dis- 

 tinguishes it from all the others. P. elongatus is closely related to P. sub- 

 quadratus, as both have the same general form, size of ambiilacral plates, 

 and sculpture, but the former is readily separated by being more elongate 

 with the sides of the theca straighter, and more especially by the far 

 greater size, being 2^ times larger than P. subquadratus. 



Oral end of the only specimen broken away, but the length seems to 

 have been about 40 mm.; width 23 mm.; depth 17 mm. 



Fig. 11. — Analysis of Pseudocrinites elongatus Schuchert. 



Occurrence. — Helderberg Formation, Keyser Member. L. Perdew's 

 farm. Pleasant Valley, west of Martin Mountain. 

 Collection. — ^U. S. National Museum. 



Pseudocrinites perdewi Schuchert 

 Plate XXXIV, Figs. 5-7; Plate XXXV, Figs. 8-10 



Pseudocrinites perdewi Schuchert, 1903, Amer. Geol., vol. xxxii, p. 238. 

 Pseudocrinites perdewi Schuchert, 1904, Smith. Misc. Col., vol. xlvii, pt. 11, 

 No. 1482, pp. 236, 237, pi. xxxvi, figs. 1-3; pi. xxxix, figs. 8-10; text fig. 32. 



Description. — General form pear-shaped, with the sides appressed. 

 Ambulacra wide, very prominent, with vertical angulated sides and fiat or 

 slightly trough-shaped oral surfaces. In specimen no. 1, the 2 am- 

 bulacra taper rapidly and extend along the periphery of the theca for one- 

 third its length. In no. 2, they are just one-half the length of the 

 theca, in no. 3, nearly two-thirds the length, while in no. 4, they are 

 about one-half the length. This shows that the length of mature 

 ambulacra is somewhat variable, extending from one-half to two-thirds 

 the thecal length. The ambulacrum nearest the anal region is always 



