96 SMITHSONIAN INSTITUTION 



PLATE XLV 

 (All figures natural size except where otherwise stated) 



PAGE 



Fig. I. Protaxocrinus elegans (Billings) 346 



Fig. I. The type, original of Billings, Decade IV, pi, 4, fig. 4a; a flattened specimen, from anterior 

 side. Shows stem with slightly alternating columnals ; angularity of lower brachials; 

 and peculiar flattening of distal ends of arms in upper part. Mus. Geological Survey 

 of Canada. 

 Trenton limestone; Ordovician. Ottawa, Canada. 



Figs. 2-7. Protaxocrinus laevis (Billings) 348 



Fig. 2. The type, original of Decade IV, pi. 4, fig. 3a; anterior view. Mus. Geological Survey of 



Canada. 

 30. Specimen from Ottawa with fewer interbrachials, anterior view; has mostly 4 IIBr 



(3 in one ray). Author's collection. 

 3&. Posterior side of same much distorted, showing large plates of the anal series resting in a 



socket on post. B. 

 4a, b. Anterior and enlarged posterior view of a fine specimen from Kirkfield, Ontario, 



showing the anal structures perfectly. It has mostly S IIBr (4 in 2 rays), and rather 



the proportions of P. elegans; but the arms are smoothly rounded. RA in form of a 



radial under r. post, ray; anal series resting in socket on right shoulder of post. B. 



Fig. 46, X 2. Author's collection. 

 Sa, b. Small specimen from Ottawa, with 3 to 4 IIBr, showing anal plates ; anterior and 



posterior views. X 2. Geological Survey of Canada. 

 6a, b. Similar specimen from Kirkfield, with 4 and S IIBr. X 2. Author's collection. 

 7. Ant'erior view of characteristic specimen from Ottawa, with stem attached. Author's 



collection. 

 Trenton limestone ; Ordovician. Canada. 



Fig. 8. Protaxocrinus girardeau n. sp 349 



Fig. 8. A specimen from near Thebes, Southern Illinois, of Richmond age ; Silurian. A recur- 

 rent form scarcely distinguishable from the Trenton species. Author's collection. 



Figs. 9-11. Protaxocrinus robustus n. sp 349 



Fig. go. The principal type specimen, from anterior radius. Author's collection. 



gb. Posterior view of same ; showing very large anal plate not attached at either side, and 



heavy arms, two of which do not branch so far as seen. X 2. 

 loa,b; II. Anterior and posterior views, and anterior view, respectively, of two other speci- 

 mens from same locality; showing presence of 3 IIBr, correlating with the short 

 robust crown of this species. Author's collection. 



Brownsport limestone ; Niagaran. Decatur County, Tennessee. 



Fig. 12. Protaxocrinus virginiensis n. sp 350 



Fig. 12. Posterior view of the only specimen ; having a very wide anal area, 3 IIBr, with much 

 slenderer and more tapering arms than the last species. Author's collection. 

 Helderbergian ; Devonian. Keyser, West Virginia. 



