212 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES. 



nearly straight line; margin rounded along the sides, less so at the anterior end, somewhat 

 angular at the rostrated posterior end; undersurface flattened, concave centrally. The apex is 

 central or subcentral. 



The ambulacral areas are rather broad in the petaloid dorsal portions, less so at the ambitus, 

 and narrow at the ends of the petals and actinally ; the petals are relatively large, broad, sub- 

 equal in length, extending two-thirds or more of the distance to the ambitus; the poriferous 

 zones are broad, though less so than the interporiferous areas, outer row of pores slitlike or 

 elongate elliptical, inner row round, pairs of pores conjugate. 



The surface of the test is closely set with small imperforate tubercles set in deep scrobi- 

 cules. The tubercles increase in size on the undersurface except along a median band which 

 is somewhat smooth but dotted with numerous granulations. 



The apical sj^stem is excentric anteriorly. There are four genital pores, the anterior pair 

 being nearer together than the posterior. The right anterior genital plate, which is modified 

 to form the madreporite, is very large, occupying the larger part of the system. There are 

 five small radial plates, each perforated by a small pore. 



The peristome is small, central, pentagonal to substellate, with a large floscelle with promi- 

 nent bourrelets and well-defined, broad, oval phyllodes. 



The periproct is oval, or subelliptical, longitudinally elongate, in a short sulcus situated 

 rather high above the posterior margin. The ends of the posterior petals are about opposite the 

 middle of the periproct. 



Related forms . — This species is similar in a number of features to Cassidulus berryi, but it 

 is more elevated, has a more rounded margin and has its peristome central instead of anteriorly 

 excentric. It also presents interesting resemblances to the Cretaceous species C. sequoreus, 

 and C. micrococcus, but can be separated from the former by its more subcircular marginal out- 

 line, its central peristome, the slightly higher position of its periproct, and the more elongate 

 character of the outer row of pores of its petals, and from the latter by its much smaller size, 

 its relatively larger floscelle, and the somewhat lower position of its periproct. 



Locality and. geologic horizon. — The specimens on which this species is founded are said to be 

 from the Miocene of North Carolina. They can not be more definitely located. 



Collection. — U. S. National Museum (9476). 



Galeeites oregonensis Dana. 



Galerites oregonensis Dana, 1849, Repv. U. S. Expl. Exped., Geology, vol. 10, p. 729, PI. II, figs. 5, 6, 6a. 

 Galerites oregonensis Gabb, 1869, Geol. Survey of California, Paleontology, vol. 2, p. 123. 



This species was based by J. D. Dana on a few fragments and spines obtained from the 

 argillaceous Astoria shale of the lower Miocene of Oregon. The spines are said to be "half an 

 inch long, very slender, delicately striate, with the strife punctate or subcrenulate." No descrip- 

 tion of the test is given and Dana himself said the "specimens are so imperfect that we refer it 

 with hesitation to the genus Galerites." In view of the imperfect character of the specimens, 

 the acceptance of the species is reserved until additional material has been obtained. 



Suborder 8TERNATA. 

 Family SPATANGIDjE. 



Genus AGASSIZIA Valentin. 



Agassizia porifera (Ravenel). 



Plate XCVII, figures la-d. 



Brissopsis poriferus Ravenel, 1848, Echinidse, recent and fossil, South Carolina, p. 4, PI. II, figs. 5, 6. 



Brissopsis iwriferus Ravenel, 1850, Am. Assoc. Adv. Sci. Proc, vol. 3, p. 160. 



Agassizia porifera McCrady,,1857., Pliocene fossils, South Carolina, pp. 5, 6, PL I, fig. 5, PI. II, fig. 4. • 



Agassizia porifera Meek, 1864, Check list, Miocene, p. 2. 



(?) Agassizia excentrica A. Agassiz, 1872, Revision of the Echini, pt. 1, p. 88. 



Agassizia porifera A. Agassiz, 1874, Revision of the Echini, pt. 4, p. 751. 



Agassizia porifera Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707. 



