CRINOIDS AND BLASTOIDS. 177 



rays have three arms each, with, exceptionally, four in one pos- 

 terior ray. In these rays the upper secondary radial toward 

 the posterior side is an axillary, and supports two arms, that 

 directed toward the anterior side quadrangular, with one arm 

 only. The arms are scarcely as long as those of the preceding 

 species: they are round and composed of medium sized pieces, 

 with straight transverse sutures. 



The interradials dorsally consist of six to eight plates in three 

 ranges. The first plate is large, and extends to the top of the 

 third radials. There are three much smaller plates in the second 

 range, and two in the third, the latter resting between the arm 



see. At the azygous side, the plates are arranged as in Dory- 

 crinus im ma turns. The first anal plate is as large as the first 

 radials. and the three succeeding plates fully equal in size to 

 the single plate at the four regular sides. The second anal 

 plate extends in height slightly beyond the level of the inter- 

 radials adjoining it. and is generally a little larger throughout. 

 This row is followed by several rows of smaller plates, which 

 lead to a subcentral anal opening. The arrangement of the 

 plates forming the vault is not known. 



Geological position, etc.: The same as the preceding species. 



Our own collection. 



DORYCRLNUS PARVIBASIS (nOV. 8p.) W. & Sp. 



PL XVII, Fig. 7. Specimen with arms from the anterior side. 



PL XVn, Fig. 9. Lateral aspect of the calyx. 



PL XVH, Fig. 9a. The same specimen, showing the ventral surface. 



This species differs from the two preceding in the form and 

 proportionate size of the basals. and in the form of the calyx. 

 It is of the type of Dorycrinus concavus from the Lower Bur- 

 lington limestone, for which Meek and Wort-hen in Vol. II, of 

 this Report, p. 214. proposed the genus Ccelocrinus. This spe- 

 cies was supposed to have no secondary radials, and upon this 

 character principally, and a slight variation in the arrangement 

 of its interradial and anal plates, the new genus was founded. 

 With regard to the absence of secondary radials. Meek and 

 Worthen were evidentlv misled. On page 214. they say: "there 

 -23 



