28 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES. 



Dimensions. — Column: Diameter of joint 5 to 8 millimeters; height of joint 1 to 1£ 

 millimeters. 



Description. — C. A. White describes and figures certain specimens as Pentacrinus asteriscus 

 Meek and Hayden that evidently belong to a different species. Springer, who has examined the 

 same material, is likewise of the opinion that the separation of the forms from P. asteriscus is 

 well founded. The name P. whitei was proposed by the author in honor of the distinguished 

 geologist who did so much to advance our knowledge of western American Mesozoic geology and 

 paleontology. 



The column joints are relatively thin, with rounded edges, and alternate with each other, so 

 that the column does not appear compactly formed when viewed from the side. A distinct 

 petaloid arrangement of the crenulated ridge is exhibited in all the forms. 



Related forms. — The species is apparently closely related to P. asteriscus, from which it is 

 separated by its generally larger alternating joints, deeper reentering angles, and less compact 

 column. 



Localities. — Salt Creek (type) and Diamond Valley, Utah (White). 



Geologic horizon. — Jurassic. 



Collection. — U. S. National Museum (8588). 



Pentacrinus shastensis Clark, n. sp. 

 Plate III, figure 4. 



Determinative characters. — Column composed of rather large pentagonal joints, with promi- 

 nent reentering angles. The crenulated ridges of the suture have a rounded petaloid arrange- 

 ment. Column perforated by a rather large canal. 



Dimensions. — Column: Diameter of joint 6 to 9 milhmeters; thickness of joint 1 to H- milli- 

 meters. 



Description. — A number of casts of column joints of a Pentacrinus of medium size have been 

 found in a very compact sandstone. They show very clearly the shape and exterior markings 

 of the joints, which have very pronounced reentering angles and sharp long rays. In one of the 

 best preserved specimens the crenulated edges of the suture present a prominent petaloid arrange- 

 ment. This is not distinguishable in most of the specimens, which are too poorly preserved to 

 show the finer details. Two of the specimens are casts of several combined joints in which the 

 side characters of the column are clearly shown. The column is perforated by a rather large 

 canal. 



Related forms. — The species is somewhat similar to P. asteriscus Meek and Hayden, but is 

 larger and of somewhat different form. 



Localities. — One-half mile north of Holcombs stage station, 4 miles north of Buzzards Koost, 

 and about 2i miles west of Buzzards Koost (type), Shasta County, Cal. 



Geologic horizon. — Jurassic. 



Collection.— U. S. National Museum (31190). 



Class STELLEKOIDEA. 

 Subclass ASTEKOIDEA. 

 Order CRYPTOZONIA. 



Family ASTERIID^. 



Genus ASTERIAS Linnaeus. 



Asterias ? dtjbium Whitfield. 

 Plate III, figure 6. 



Asterias"! dubium Whitfield, 1877, Preliminary report on the paleontology of the Black Hills, p. 15. 

 Asterias"? dubium Whitfield, 1880, Paleontology of the Black Hills of Dakota, pp. 344, 345, PI. Ill, fig. 3. 

 Asterias dubium Clark, 1893, Johns Hopkins Univ. Circ, vol. 12, No. 103, p. 51. 

 Asterias"? dubium Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 31, 32, PI. V, fig. 2. 

 Asterias dubium Logan, 1900, Kansas Univ. Quart., vol. 9, pp. 130, 131, PI. XXV, fig. 4. 



