286 CRETACEOUS PALEONTOLOGY. 



the poriferous zones are narrow, slightly sinuous, three or four 

 pairs of pores in each plate disposed in a curved series about the 

 margin. Interambulacral areas about one and one-half times the 

 width of the ambulacral, with two rows of primary tubercles 

 somewhat larger than, but similar to those of the ambulacral 

 areas ; in addition there are several irregular rows of secondary 

 tubercles, of various sizes, that are most numerous between the 

 rows of primary tubercles and the poriferous zones, and also 

 scattered, flattened granules. The primary tubercles of both the 

 ambulacral and interambulacral areas have wide, circular areolas, 

 elevated and deeply crenulated bosses, and distinctly perforated 

 mamelons. The oral opening is narrow, scarcely more than one- 

 third the diameter of the test, with slight marginal incisions. The 

 discal opening pentagonal. 



The dimensions of a complete test are : height, 12.5 mm. ; width, 

 31.25 mm. 



Formation and locality. Vincentown limesand, Vincentown 

 (154) ; Timber Creek (Clark). 



Geographic distribution. New Jersey. 



Pseudodiadema speciosum (Clark). 

 Plate IX., Figs. 7-14. 



1891. Cyphosoma speciosum Clark, Johns Hopkins Univ. Circ., 



vol. 10, No. 87, p. 76. 

 1893. Coptosoma speciosum Clark, Johns Hopkins Univ. Circ., 



vol. 12, No. 103, p. 51. 

 1893. Coptosoma speciosum Clark, Bull. U. S. G. S., No. 97, p. 



52, pi. 1 8, figs, i a-h. 

 1905. Coptosotna speciosum Johns., Proc. Acad. Nat. Sci. Phil. 



1905, p. 6. 



Description.. Test circular, inflated at the sides, both poles 

 flattened, the oral more than the aboral. Ambulacral areas wide 

 and prominent, with two rows of primary tubercles of 12 or 13 

 each, which gradually diminish in size towards the poles; the 

 areolas are nearly confluent above and below, and are marked by 

 irregular radiating ridges; the bosses are deeply crenulate and 



