236 Systematic Paleontology 



Genus PSEUDOCRINITES Pearce 



PsEUDOCRiNiTES GOKDONi Schiichert 



Plate XXXIII, Figs. 5-9 ; Plate XXXV, Figs. 11-13 



Pseudocrinites gordoni Schuchert, 1903, Amer. Geol., vol. xxxii, p. 235. 

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



No. 1482, pp. 229-231, pi. xxxvi, figs. 8-12; pi. xxxix, figs. 11-13; text fig. 



29. 



Description. — Ambulacra angularly elevated, prominent, extending 

 around the entire periphery of the theca, and touching the column in speci- 

 mens 20 mm. or more in length. In some of these mature specimens the 

 ambulacra, when near the column, are deflected, and one or both will pass 

 on the same side for a short distance in front of it. In smaller specimens 

 the ambulacra do not quite reach the column, and in one having a thecal 

 length of 15 mm. they stop within 3 mm. of the stalk. In the largest 

 specimen there are 40 brachioles on each side of an ambulacrum, while in 

 one having a thecal length of 15 mm. there are about 21. Length of 

 brachioles not definitely kno\\Ti ; those of the apical region not less than 

 11 mm., stout, and with about 17 pieces in each column. Ambulacral 

 groove wide and covered by a complex series of small and large ambu- 

 lacralia. Basal pectinirhomb smal-lest, in the largest specimen having 

 about 80 grooves; that on plates 12 and IS has about 90, and the one on 

 plates 1-4 and 15 is the largest, with about 120. Hydropore minute, closely 

 adjoining the madreporite. Anal pyramid depressed, consisting of 7 some- 

 what ornamented plates surrounded by a circle of 8 larger plates of irregu- 

 lar size and definite sculpture. Column slender. Length unknown. 



P. gordoni is the most prolific of American Pseudocrinites. The nearly 

 circular outline of the theca and the greater number of brachioles dis- 

 tinguish this species from P. clarH and P. perdewi. Of forms with nearly 

 circular theca P. stellatus differs in the very prominent sculpturing and 

 the smaller number of brachioles, while P. daijpolei differs in the vermi- 

 form sculpturing and fewer brachioles. 



P. gordoni undergoes but little modification in form. In general the 

 outline is circular, but occasionally a specimen is a little more elongate 

 and in rare cases one is more transverse. Of the latter, one has a thecal 

 length of 29 mm.; breadth 33 mm.; and deptli 19 mm. There is very 



