GIRTY, THE WEWOKA FORMATION OF OKLAHOMA 123 



small, creuulated about the circumference, and with a diminutive round axial 

 canal. The basals are irregularly hexagonal, shaped more like a triangle 

 with its basal angles truncated. That to the right of the azygous plates is 

 slightly larger than the others and not symmetrical. 



The radials are seven-sided, twice as wide as high, the base of the heptagon 

 being uppermost and very long. The two apical sides are also long and some- 

 what concave, while the two lateral sides are short. The two plates near the 

 azygous group are unsymmetrical, and have the apical sides of unequal 

 length. Just below the upper margin of each of the radials occurs a short 

 slit-like excavation. Above this on the broad upper side of the plate, there 

 is a triangular depression defined by two elevations or ridges which also bend 

 outward and extend along the outer margin of the upper surface. A some- 

 what similar triangular excavation marks the inner side of the upper edge 

 of the thick plate. 



The azygous basal is subquadrate, much longer than wide, in reality being 

 T-sided with a relatively broad base. The sides are formed by a broken line 

 of which the lower portion is much shorter than the upper. The upper side 

 is also made by a broken line, the dextral part of which is long and oblique 

 and the sinistral short, merely truncating the angle which the other would 

 otherwise make with the left side. This plnte is therefore bounded below by 

 the infrabasal, on the right and left sides by the basal and the radial, and 

 on the upper side by the two other azygous plates. The second and third 

 azygous plates are missing from the specimen, as are also the brachials. 



Ht/drrionocrinus patidus resembles H. discoidalis and H. crassidiscus. 

 From the former it may be distinguished by its larger size, more convex 

 plates, granulose surface and by the shape and arrangement of the 

 azygous plates. The azygous basal in the present species is differently 

 shaped, so that it is in contact at the right with the radial, thus sepa- 

 rating the second azygous plate from the adjacent basal on that side. 



The relationship with crassidiscus is rather more close. The basals 

 ("subradials") are however described as all hexagonal, while here they 

 are five-sided, except the azygous one, which is seven-sided. The azygous 

 basal does not in crassidiscus reach the second basal "as is usual in this 

 genus."' Furthermore, in the present species, the second azygous plate 

 intervenes between the first and the radial to the right. 



Horizon and locality : Wewoka formation ; TVewoka quadrangle, Okla. 



Annelida 



Enchostoma serpuliforme sp. nov. 



Attached to a large undetermined Orthocoras are some slender tubular 

 organisms seeming to belong to the genus Enchostoma. One, from which the 

 present description is drawn, has a diameter of 1 nun. or less ami winds 

 about on the Orthoceras to a length of almosl i W nun., without appreciably 



